Alexander J. Glass

Bromberg:

Why don't we begin by talking about how you came to go to IDA, and what was going on, what your work involvement was.

Glass:

Well, I got to go to IDA in part through the good offices of Keith Brueckner, in part through the peculiar circumstances that surrounded my graduate studies at Yale with Gregory Breit. Breit was a very strong mentor, very domineering, and unfortunately, he took a liking to me, so he indicated that he didn't want to let me go, and asked me the kind of position I'd like, and I said I was looking for an academic position, and he said, "I can think of no academic position that would suit you better than the one I'm prepared to offer you." And since he was a leading figure in physics, and it's very hard to get anywhere without his recommendation — so I was despairing, because I really wanted to get away from him, and through a fellow named Ken Greider, who was on the faculty at Yale at that time, he put me in touch with Keith Brueckner and IDA. I went down and interviewed with Brueckner and I got an offer from him, and I was very pleased about that. Whatever else can be said of Gregory Breit, he was a patriot, and so he said, "Well, if it's something to do with the national defense, I won't stand in your way." So that's how I wound up at the Institute for Defense Analysis. I had just gotten my Ph.D. and done a one year post-doctoral with Breit.

Bromberg:

Were you going down there to do the kind of work you'd been doing with Breit?

Glass:

No, I was going down there explicitly to get away from the work I'd been doing with Breit.

Bromberg:

I see.

Glass:

My work with Breit was computational atomic physics. Breit was a nuclear physicist. We were working on some problems related to hyperfine structure, where the atomic physics had to be understood in order to unravel the details of the nuclear physics, and what I had done was primarily a large scale numerical computation, large for its day. Today I could do it on a Macintosh. But I wanted to get away from nuclear physics because I thought it was a field that was dominated by senior people and there were too many authorities. But I didn't have a clear assignment when I went to IDA. In fact, I was given the choice of working in two areas. One was upper atmosphere physics, which is more in line with the atomic physics I had been doing, what in those days was called re-entry physics, and it was associated with the problems of the signatures of re-entry bodies and could you tell from the reaction of the upper atmosphere any of the characteristics of the body that was re-entering, things like that. The other area that was new and where they needed help was in the laser area, and that group, at IDA, was very small, headed by Bill Culver, and I talked to Bill, and I remember, I had one weekend in which to make a decision, the first week I went — I reported in for work on Friday and I had to by Monday say which field I wanted to go into, of the two. I took home a book on each subject, and didn't read them. I just thought about the people that I'd be working within the two fields, and I thought that with Bill Culver I would have more fun and learn more, so I said, all right, I think I'll opt for the laser project, and that's how I got into the laser group. So I never regretted it. The group consisted of myself, Bill Culver, and John Walsh. John is now at the Naval Research Lab. We were assisting what in those days was ARPA, now DARPA, in the conduct of the laser program, but of course this was 1964, so lasers were new, Q switching was about two years old, nonlinear optics was brand new. And it was a very, very exciting time.

Bromberg:

Now, when you are doing that, do you spend some time monitoring contracts or do you just do research or what? I know that you wrote a number of reports while you were there.

Glass:

We operated very much the way say Schaefer Associates operates today, except we were not for profit. We were an extension of the ARPA staff. We provided them with, we had access, because we were non-competitive, we had access to all the contract reports. We did technical analysis. I concentrated primarily on the nonlinear optics of the atmosphere, high intensity light propagation in the atmosphere, stimulated Raman scattering, thermal blooming, other stimulated processes in the atmosphere, as well as the passive properties of the atmosphere, — that is, absorption, aerosol scattering, water vapor and so on.

Bromberg:

Now, at this time Townes was also as I understand it doing some work on all of that at MIT, thermal blooming and — at least this is my impression.

Glass:

I don't recall Townes. Keith Brueckner and Siebe Jorna had done some analysis on thermal blooming . Brueckner analyzed it in the form of a propagation instability , a very elegant paper.

Bromberg:

Brueckner was at San Diego at this point?

Glass:

Brueckner was at San Diego. See, Brueckner was at IDA when I first went there, but then he left very shortly. We had an advisory group, which was sort of the honor roll of people in lasers and nonlinear optics at the time, including Normal Kroll, Nico Bloembergen and Charlie Townes, Keith Brueckner. Those were the main people I interacted with. In terms of experiments in thermal blooming, the first direct experimental observation of the index changes associated with thermal blooming we did at NRL, after I went there. But what Townes had done — he was concentrating more on self-focusing. He did experiments with Ray Chiao. There was a lot of controversy at the time as to whether or not you could form a stationary filament, and Townes was on one side of it and some Soviets were on another side of it. It was a fairly spirited discussion. But as far as thermal blooming was concerned, I think Brueckner was the first guy to do the analysis of the problem. He looked at it in terms of — he linearized the problem like a plasma physicist, did it as a — you know, calculated the threshhold.

Bromberg:

OK, but it sounds as if it was a pretty constant interchange with your advisory committee, is that a right —?

Glass:

Yes. Oh yes, absolutely. And we had very extensive summer studies. Of course, the Jason group was active.

Bromberg:

How did the Jason group interact with your group at IDA?

Glass:

Well, IDA was the housekeeper for Jason.

Bromberg:

OK. I know that Townes started Jason when he was at IDA.

Glass:

And there had been a summer study in 1963 on use of lasers for ballistic missile defense, which was seminal , and at which many of these issues were first raised. And that was —so that was the first, that was the point of departure for a lot of our discussions, was the '63 summer study.

Bromberg:

So that I should be thinking of you as organizing, say in the laser group, as organizing the summer study?

Glass:

No. No. I was a participant in the summer studies. My work was primarily technical.

Bromberg:

And then you were a participant at Jason meetings?

Glass:

No, we didn't. Occasionally we'd be asked to go and give a briefing, but that would be the extent of it. We were primarily an adjunct to ARPA, so Glenn Sherwood was running the laser program at ARPA at that time. It was a small program. After all, lasers were really just beginning. But there was an intensive effort at ARPA to see what the prospect for lasers was in ballistic missile defense. And my primary interactions were with Glenn, and then with the contractors. I spent a lot of time talking with and dealing with the funding agencies, AFOSR, ONR, etc. Not on questions of budget so much as programmatics and technical issues.

Bromberg:

For example, you would be following — I have a note in my files that you would be somebody who knew about the work of TRG, is that ?

Glass:

That's right. Marshall Harrington, who was the contract monitor, for TRG, at AFOSR , I remember very clearly, came all the way -that was one of the first meetings, I had just joined, one of the first meetings I sat in on, involving an outside contractor, contract research he was describing the work at TRG, and what they hoped to accomplish, and then subsequently I visited TRG, so yes, that would be — part of my job was to be able to tell , to give Glenn Sherwood an independent evaluation of how things were going with these various contract research programs.

Bromberg:

So for example is that something we can talk about? It would certainly be interesting to get an IDA eye view of TRG , as opposed to — of course we've talked to some of the people who were in TRG.

Glass:

Well, it's not an IDA eye view, it's just my own view.

Bromberg:

But it is from a different position in the scheme of things.

Glass:

I was a little disappointed at what came out of that contract. It was a marvelous contract. They had a three year contract, carte blanche, all funded, and they had free rein to do, basically to do whatever they wanted to. And I think the net output was minimal.

Bromberg:

Now, they got a contract already in 1959, that celebrated one million dollar contract, when they had put in for $300,00. Is that the one that you're —

Glass:

No.

Bromberg:

This is a follow up?

Glass:

I think it must have been '64, '66 or something like that.

Bromberg:

OK. And it was another very generous contract?

Glass:

Well, it seemed generous to me at the time. But the main thing about it was, it was very liberal in terms of what they would do. Basically it was level of effort funding. They were given funding and told, OK, you can basically do what you want, invent, be smart. And as I say, my impression at the time was that we weren't getting a whole lot out of it.

Bromberg:

Did they hire the people you would have liked to see them hire?

Glass:

I was not in a position really to make that judgment. The people who were there seemed very capable to me. Gordon Gold of course was there, Dick Daley, who subsequently went off to —

Bromberg:

Jacobs, probably, Rabinowitz?

Glass:

Yes, the people who went to Brooklyn Poly.

Bromberg:

Latourette?

Glass:

Yes. All very good people, in retrospect, they were all very good people. It may have been that they weren't — that they could have benefitted from a tighter focus. Looking back at it from a vantage point of more years than I care to remember, 20 years, they might have done better had they been able to define the objectives better. I don't know. But I remember at the time, as we went along, thinking, we aren't getting — it seemed to somebody just out of graduate school, that seemed like an ideal situation , somebody gives you money and doesn't hold your feet to the fire — and yet I didn't think we got a lot out of it. Shortly thereafter — I think there was a lot going on inside the organization that I was not aware of at the time —

Bromberg:

I know, they broke up a little after that.

Glass:

It wasn't very much longer, very much after that, that CDC bought the company and basically disbanded it, people were dispersed. So I was not really sensitive to those internal tensions, and that may have had a lot to do with it.

Bromberg:

What about some of the other contracts that you had a good oversight on ? Were you involved with any of the Hughes contracts?

Glass:

Yes. I remember going out and spending quite a bit of time talking to Bob Hellwarth and Fred McClung at Hughes, Hughes Research setup. I was very impressed by the work that was done there. I think, in contrast to whatever reservations I had about TRG, I had no reservations about the work at Hughes.

Bromberg:

This is the time Bill Bridges was working on the ion laser?

Glass:

That's right. And as I say, I dealt mostly with Bob Hellwarth and Fred McClung, because they were working on simulated Raman scattering.

Bromberg:

Well, now, Bob Seidel writes to me that Culver was an enthusiast for the Seaside program, at this conclusion, and he would — in the anti-ballistic missile programs — and he would be very interested to know what other people in the group, whether they shared that enthusiasm at the time or?

Glass:

Culver —- Bill is an enthusiast, period. Anything Bill's involved with, he's an enthusiast for. He's a very enthusiastic, positive, energetic guy. And he was a great — and here I was, just coming out of graduate school, and having worked under a very difficult taskmaster, and it was like being let out of prison to work with Culver. It was just diametrically opposed. I also of course had access to the senior advisory group. It was just wonderful. I learned a great deal, more probably in the two years at IDA than in four or six years of graduate school, or so it seemed at the time. So yes, Bill was an enthusiast. I spent a lot of time, a great deal of time, preaching the gospel of the atmosphere, saying, "You've got to keep — the atmosphere will not support the propagation of high powered laser beams, for a number of reasons. "If it's high average power, then you've got thermal blooming. If it's high peak power, you've got stimulated Raman scattering. Recently, of course, I was participating in the SDI study for the American Physical Society, and I went back and literally dug up a 20 year old note, and the only thing that had changed, we had a little better data on some of the phenomena. The analysis was no different than it was when Brueckner did the basis , when the Brueckner and Townes people did the basic first cut analysis in 1964, '65. Nothing has changed. The atmosphere is still the atmosphere, and the prospects of getting a high powered laser beam through the atmosphere are no better now than they were then.

Bromberg:

Were people like Brueckner and Kroll also preaching the gospel of the atmosphere?

Glass:

Sure.

Bromberg:

Was Walsh? I mean?

Glass:

— well, it was my purview that I was primarily concerned about, the atmospheric propagation part of things. Yes, Norman Kroll — I had the privilege to work with Norman Kroll on analysis of stimulated Raman scattering. I think it was clear to everyone where the problems lay.

Bromberg:

What effect did this have on the programs that were being run on the Seaside program for example? I mean, what I'm getting is a feeling that coming out of IDA is all this cautionary stuff, coming to Sherwood or whoever. What happened then?

Glass:

Well, you have to bear in mind that we were coming up with numbers — for example, average power limits which were peak power limits say which were in the hundreds of megawatts, a few hundred megawatts diffraction limited , in a diffraction limited beam at 1 micron, that calculated with stimulated Raman scattering in the atmosphere. We didn't have a laser that could produce that. So it was, people said, yes, we'd be delighted if we had that problem, and the primary emphasis in the ARPA program was on the development of technology. So there really wasn't — I mean, we were so far removed from any real system, it wasn't even possible to test things. We did do some experiments on thermal blooming at the Air Force Weapons Lab, Pete Avizonis and Art Guenther, and these were some of the earliest experiments that we really observed thermal blooming in high powered beams, because they had a high powered laser there. I remember Brueckner commented about this experiment, he said, "All you've done is show that a heated gas expands." Which is true, but it was necessary to perform what you might call admiral's test because we were dealing with admirals. We really were dealing with people who had to see things in order to believe them. But things were at a very elementary stage, and I must say that now, with the current interest in SDI, I see things being discussed that were, to my mind, laid to rest 20 years ago. Oh, absolutely. Absolutely. It's just that another generation of scientists have come along , and done the calculations, except that now there are data that support these conclusions in fine detail. We could only do — we didn't have all the details about things like line widths that are associated with the Raman scattering process. We didn't have — we could make estimates on those sorts of things, but within the accuracy of the estimates, the phenomena —

Bromberg:

— now, I'd like to go back to this collaboration with Guenther and Avizonis, because you did so much collaboration later on, at least with Guenther —

Glass:

— yes—

Bromberg:

— that I'm just interested in how that got started.

Glass:

It started because we had some — there were endless meetings, of course, typical government style.

Bromberg:

I see.

Glass:

Everybody was — there was sort of a group of 20 people that were constantly meeting with each other, in one or another venue. Sometimes it was Albuquerque. Sometimes it was Washington. Sometimes it was California or whatever.

Bromberg:

Did these guys work on the advisory committee?

Glass:

No, these guys were in the laboratory. They were doing the work. And there were only a few laboratories that had large lasers. So when I learned that, see, Pete and Art, Pete Avizonis and Art Guenther were going to do some experiments on stimulated Raman scattering in hydrogen, and there had been experiments — I should back up. There had been a number of experiments done on stimulated Raman scattering in organic liquids, and these showed profound anomalies. The reason was, they were not experiments in stimulated Raman scattering, they were experiments on self-focusing. The beams were self-focusing. The Raman scattering was simply evidence of self-focusing. So people were assigning what they called thresholds for stimulated Raman scattering to a number that was, to conditions that were really representative of threshhold self-focusing, so it was clear that one had to do experiments in gasses where the self-focusing would be much less important.

Bromberg:

Now, I always think of this as being just clarified during the time you were at IDA, I mean, with the Puerto Rico meeting in "65 and so on, and so I get — I mean, in my head, this is going to be a period of confusion in this whole thing at the very time that you're doing these experiments, is that a —?

Glass:

That's what I'm saying. That's what I'm saying.

Bromberg:

I see.

Glass:

There was confusion.

Bromberg:

But you knew that you had to do the gasses because —

Glass:

— sure. That was pretty clear. I mean, if you do a calculation — we knew, we pretty much knew — people like Paul Kelley at Lincoln Labs, Kroll, a number of other people had — it wasn't very hard to calculate what the competition would be between self-focusing and Raman scattering. You might not get all the details right, but you'd get threshold estimates.

Bromberg:

OK.

Glass:

And it was clearly of interest to move to a medium in which the self-focusing was less pronounced than it was in organic liquids. We did some experiments on hydrogen. Bloembergen had done — it was actually either George Bret or Pierre Lallemand who were working with Bloembergen — who did some work on stimulated Raman scattering in hydrogen, and it seemed to be free of the anomalies which were plaguing the organic liquids.

Bromberg:

I see.

Glass:

Then we did some —

Bromberg:

But that was a kind of a first — you felt you had

Glass:

— if I remember right, those were the first data that I saw, the ones that came out of Harvard. Then — and by the way, a lot of the motivation for that was, the reason, we were looking at Raman scattering at IDA, driven by Culver, because we were interested in the backward traveling Raman amplifier , as a way of cleaning up laser beams. Yes. Yes, I mean, the day I walked into IDA, for my interview, Bill Culver discussed that with me. The fact that a — if the pump beam and the amplified beam, signal beam, moved in opposite directions through a Raman medium, you'd get a beam cleanup. And I remember Bill describing that very vividly. He described that that was a way of getting around the poor beam quality that was plaguing high powered lasers in this, particularly glass (gas?) lasers. So that was the other motivation for it. That was more the motivation than atmospheric issues. That was the motivation for pursuing Raman scattering in its own right. My interest in Raman scattering in the atmosphere was really secondary.

Bromberg:

I see. And how did that come out?

Glass:

Well, the way it came out was that indeed, it worked — as you probably know, Western research today is heavily funded by SDI, to do precisely that. But those things were all done — I mean, Bloembergen made a backward traveling Raman amplifier in his laboratory in the sixties, and then Culver went off to, when Culver left IDA and went to RDM, he set up a fairly good sized experiment on that too. And as I say, in the meantime Avizonis started to do some work on hydrogen Raman amplifiers too. But how it wound up, by the way, was that indeed, it works, but you pay a penalty in efficiency. You give away energy when you do that conversion. It turned out to be more efficient to clean up the beam in the high powered laser, and that was accomplished, more than anything else, through the use of special filtering, John Hunt's invention, at Livermore.

Bromberg:

So then during the period you were active on this —

Glass:

That came ten years later.

Bromberg:

OK, that's what I wanted to know. During the period when you were active on this, you didn't know yet that, about this energy penalty, or you?

Glass:

Oh sure , we knew the energy penalty, but we didn't know there was an alternative.

Bromberg:

OK. So now —

Glass:

— we were dealing with lasers that had very, very poor spacial multi-panels. So that the ability to clean up a bad beam seemed like a very attractive thing to do. There were other advantages. Western research uses it today. You can combine several beams to pump a single beam, so it's a way of beam combining, combining apertures. It also provides you with pulse shortening capabilities and pulse compression capabilities, and we knew about that too.

Bromberg:

— you were already thinking —

Glass:

Culver showed me those calculations in '64, '65.

Bromberg:

Was pulse shortening of interest in any connection at that point?

Glass:

Yes. It was of interest in general. This was before mode lock had been —

Bromberg:

— yes, it was just around, I guess.

Glass:

Discussions were going on, because I remember when Tony De Maria came down and talked for the first time about mode locking. And people were pretty skeptical. Here was this Italian guy — didn't look like the standard Harvard scholar — and people were a little reluctant. They didn't understand it, they weren't sure what he was talking about. At IDA we were very impressed by Tony. But prior to the introduction of mode locking, we didn't have a good way to make 7 nanosecond pulses, store pulse compression by the Raman scattering looked like an attractive way to do that.

Bromberg:

Is this pulse compression, these shorter pulses, is that at this time just something you thought was interesting, would obviously be useful, or was that something that was very much tied to a need, a requirement ?

Glass:

We weren't — you see the field was very new at that time, so we were ,I personally was just interested in things that were new. We didn't know where it was going to take us. So things that were of academic and scientific interest were of interest. We didn't restrict ourselves. We really didn't know — I remember at the time, I had files on every conceivable application of lasers, including laser fusion, which was only whispered about. I mean, Basov gave his paper in 1963, where he talked about it, but the fact that you used the laser to oblate the target and achieve the compression, that was still classified. But anyway, there were a lot of applications. I had files on applications, and anything that looked new and interesting, we looked at.

Bromberg:

OK. So then...

Bromberg:

This was the first collaboration that Dr. Glass was doing, the theoretical work for this experiment.

Glass:

Also I gave some lectures on laser physics and nonlinear optics to the staff at the Air Force Weapons lab.

Bromberg:

By the way, I know Breit as a theorist did —- were you also doing experiments at this point?

Glass:

No.

Bromberg:

So everything you were doing now is analysis.

Glass:

Theoretical or computational. Yes, that's right.

Bromberg:

OK, well, what about, let's talk a little bit about the gas dynamic laser. You were there for some of that. That's very important.

Glass:

Abe Hertzberg came in to talk about the gas dynamic laser, and I can't remember the exact sequence of events involving Hertzberg on the one hand and Ed Gerry and Arthur Kantrowitz on the other. I remember one meeting of the advisory committee, IDA, and Hertzberg was explaining the action of the gas dynamic laser in very much engineering terms, and having a good deal of difficulty getting that information across to the assembled physicists. They were Nobel laureate quality physicists, but they had trouble understanding wave diagrams, which is the way mechanical engineers look at these things, space time diagrams. Anyway, Abe came in and talked about gas dynamic lasers, and then — and there were a lot of discussions at IDA that I was not a party to — but it created a tremendous amount of interest, and a study group was put together, to convene in California, and I remember I received, I think was already at the Naval Research Lab at this time, because I received a telex sort of ordering me to proceed to Los Angeles, and not to tell anyone where I was going or why. It was all very hush-hush, and we had a two week meeting at the air Force office just near the Los Angeles Airport, looking on all aspects of the gas dynamic laser. I was looking at the atmospheric side of it, thermal blooming.

Bromberg:

Who called this meeting?

Glass:

The Air Force.

Bromberg:

OK, and who was there, as far as you can tell me? What kinds of people? It was a group of scientists?

Glass:

It was a group of scientists, yes. I believe Paul Kelley was there. Hal Jura from Rand, I believe Guenther and Avizonis were there, those are the people who come to mind. I'm sure there were others too.

Bromberg:

You were looking at both Hertzberg and Avcozor you were looking mostly at Avco?

Glass:

We were looking at high powered CO₂ lasers. There was a name, an acronym, but that was the 8th card program, was the code name. But it was called — there have been so many studies with the same acronym — it might have been HELP or something like HELRIG, no, that was later — I can't remember. Maybe it was the HELP study — high energy lasers something. But in any case the program was given the code name 8th grade. A meeting was held then in Florida, because Pratt & Whitney was setting up to do experiments in Florida. The meeting was held in Florida. It was a DOD meeting, and Kantrowitz gave a talk on the AVCO work, and before the talk, the chair, whoever it was , go up and said, "This is not only secret, this is really secret. What you're about to hear, this information is to be protected. We really mean it. This is secret. " And within about a month of that meeting, several people in the Boston area had given lectures to uncleared audiences on the gas dynamic laser, to the extent that there was an investigation of whether — I was asked, I was at NRL at that time, I was asked , you know, to participate in the damage assessment, what had really —

Bromberg:

Oh, really?

Glass:

Yes. It was a serious release of information.

Bromberg:

That is, the AVCO people had given this?

Glass:

No, no. Someone at the meeting, someone in attendance at the meeting, a university consultant, who then went back and gave lectures in which he included this material, and it impressed me at the time because as far as I know, absolutely nothing was done about it. It was a very fundamental breach of security.

Bromberg:

Didn't he lose his security clearance?

Glass:

Not as far as I know.

Bromberg:

Of course I know of incidents like that, at the very time when they were pillorying Oppenheimer, that you had incidents like that taking place. But I've heard that there was a lot of, or at least a certain amount of opposition to the whole gas dynamic laser, particularly from people who were very much interested in solid state lasers. Was that a false — do you have any memory of that?

Glass:

— It would be remarkable if that were not the case. At every point in the laser business, every new advance has been opposed by the advocates of some other technology. I was on the side of the enthusiasts, so, I mean, there were a lot of different technologies, and my feeling at the time, and I think the feeling of the people in ARPA, was that you know, we knew we weren't getting very far with solid state lasers, had been discounted for ballistic missile defense or for anti-aircraft purposes a long time before, in most people's minds. This was a — what had happened, let's step back and look at the evolution of the CO₂ laser — Patelle reported the operation of the CO₂ laser first in 1965 or so.

Bromberg:

Probably a little earlier.

Glass:

Yes. And at first, the power output was miniscule. Then a variety of improvements were made, and the sort of reductio ad absurdem of the glow discharge CO₂ laser was a kilowatt system that Raytheon built, that — it's very vivid in my mind because it had hundreds of meters of water-cooled glow discharge pipes this big, glass pipes, and there were algae growing in the water, in this water-coupled swimming pool, and that was a kilowatt, and it was a tour de force but still, in fact, there was a contract let. Raytheon — it's the last gasp of TRG — Raytheon, TRG and Hughes, I think, all bid on building a kilowatt CO₂ laser, and I don't think TRG built theirs. Raytheon built this big monster. It was clear that that technology, if it was going to go anywhere, was going to need some new ideas, and the gas dynamic laser seemed to offer those new ideas. It offered a significant step up. So from that point of view, it was greeted on the part of people who were looking for high powered systems, greeted with enthusiasm, and I don't feel it was ever in competition with solid state lasers.

Bromberg:

OK, and so the opposition that I've heard about never really jelled into a confrontation that needs to be commented on?

Glass:

I don't know anything about it. If it happened, it happened behind closed doors. I wasn't party to it.

Bromberg:

Another thing, you talked a little bit about the effects of classification. Is there anything else in your experience with the gas dynamic laser, where its ultra-severe classification played any role in the actual development, is that something that's worth —?

Glass:

I don't think so. I don't think so. I think that the period of ultra-severe classification didn't last that long. And it wasn't that — well, there were several groups working on the gas dynamic laser, within the defense community. Everybody was cleared so there was not — there was a special access program which made it a little more difficult, but at IDA and subsequently NRL, I had whatever access i needed, so that I didn’t find that it was restrictive.

Bromberg:

There are actually two concerns that AAAS has been having recently that it would be nice to collect some data on. They have been very interested in the role of secrecy in science, they ran a panel on that. They're presently running a panel on the use of peer review by government agencies in evaluating contracts and so on, and so I just thought that if anything here was relevant to those interests, I might —

Bromberg:

Of course, what I'm especially interested in is what that tells about the way in which ARPA and IDA and perhaps other agencies I don't know considered peer review in those days. I'm trying to extrapolate back to the historical atmosphere, the attitude, —

Glass:

Certainly there was a lively debate on new ideas. People who had new ideas brought them to meetings at which representatives of the various funding agencies were present, IDA people were present, the university consultants were present, and we hammered things out. Now, that may have been peer review, but it was peer review face to face. It was in an active mode.

Bromberg:

The only thing I've so far come across in the laser field on this, I have come across a review that Townes did early on of the Gould proposal. Now, that was in the beginning of '59. That's the only evidence I've ever seen of a proposal shipped out to an academic —

Glass:

Oh, people were reviewing. I mean there were written reviews on proposals during all this time. But as I say, a lot of it was done in fairly rapid fashion. It was a fast moving program.

Bromberg:

OK, that's another aspect.

Glass:

Also there was this group which probably still exists. Peter Franken headed it for a while. Bob Collins headed it for a while. It was called the Advisory Group on, it was part of the Advisory Group on Electron Devices, Special Group on Optical Masers of the Advisory Group on Electronic Devices, that looked at all contracts, the quality of the contracts in the laser area. That is to say, Peter headed it, then Bob Collins, and there were good people on that, representatives of all the different funding agencies plus there was the consultants as well. This was not so much to review proposals as it was to coordinate activities to exchange information, so that the Air Force would know what the Navy was doing and vice versa. And I think it was fairly effective.

Bromberg:

Then there's another program that I mentioned that I'd like to — no, I guess the Seaside, —

Glass:

One of the things that should be pointed out, within IDA itself there was a lot of skepticism on the part of the people who had spent years and years looking at the application of radar and missiles, ballistic missile defense, a lot of skepticism about the role of laser technology. Those of us who were the laser enthusiasts were viewed with a little I think healthy suspicion. Of course we were talking about technology that didn't exist yet, and they were struggling with the real technology, but I think that, you know, within the organization , it was by no means clear sailing for the laser enthusiasts. I remember very very intense discussions and highly critical debates about the role of laser technology in ballistic missile defense, conducted within IDA. There were people there, there was a group of people, still is, as a matter of fact, very knowledgeable in infra-red technology, Lucius Biberman and his collaborators. There were a lot of people with background in microwave radar and so on. And we were looking at lasers not only as weapons. We were also looking at lasers for optical radar, lasers as discriminators, and so forth. So there was, when you talk about debate and criticism, a lot of it came from within the ballistic missile defense community. And the great virtue of IDA was, they weren't selling just a single approach. There were people there who represented a whole range of approaches.

Bromberg:

Did your group grow, or was it just the three of you, these two years?

Glass:

It was just the three of us, with some consultants.

Bromberg:

About how large was IDA as a whole?

Glass:

Well, IDA had several divisions. The division we were in, which was what's called research and engineering support division. It was — our group — there was a weapons evaluations group, there was also, there was another part of it too, but we were maybe 65, 75 people, somewhere around that.

Bromberg:

And with this free discussion right across divisions?

Glass:

Oh yes. All the people I'm talking about were mainly within the same division.

Bromberg:

OK.

Glass:

We worked on different tasks, too. I spent some time on some infrared tests, as well as on laser tests, so we had a lot of going into the next office and having discussions, where you think about something and you need a sounding board and you wander into the next office. It was a very — by the way, IDA in those days was a very, it was a delightful atmosphere, wonderful.

Bromberg:

That's really interesting, because when I first looked into IDA, I'd have to say —

Glass:

— yes, particularly for someone just out of graduate school, working in a new field, the laser field, who had access to absolutely the top people in the country.

Bromberg:

Let me see if there are any other questions I've got here before we — Well, why don't we talk about the Naval Research Laboratory now? First of all, why did you decide then to move from IDA to NRL?

Glass:

Well, I went to IDA really with the idea of being there for two years, when I went there — and IDA at the time was encouraging people to sort of come in and spend a few years and then go back out, so they'd become familiar with defense problems. And I had been talking with Alan Kolb at the Naval Research Lab. Alan was heading the plasma physics division, and he wanted to set up a laser group, and I was a little frustrated at not having any, although I'm not an experimentalist, I wanted to be in a position where I could more directly influence I could do experiments that needed to be done, so Alan offered me that opportunity, asked me to come in and set up the laser physics branch at the Naval Research Lab, which I did.

Bromberg:

Now, what was there at that point? There was just plasma physics?

Glass:

There was plasma, yes. There were (crosstalk )

Bromberg:

— you had some laser work done at NRL, I'm thinking of the telescope —

Glass:

Yes. That's a very different technology. Sure, that telescope still sits on top of the administration building. The one that had the first maser on it.

Bromberg:

Oh good, I hope to get down there.

Glass:

Made history. But that was very far afield. There was a commitment from the laboratory to make space available, although we were working primarily on DARPA funds. In fact, I think in the whole plasma physics division, I don't think there was any Navy money, or a very small amount.

Bromberg:

I see, so you came in and then got a DARPA contract to —

Glass:

McCallum had already been talking to DARPA about this, so the way was paved. When I came in we had about, it seemed like a lot at the time, it was a half million dollars, it doesn't seem like much now — to set up the laser physics branch, and John McMahon was the principal experimentalist.

Bromberg:

I see.

Glass:

So we built up a ruby laser facility to do some of these Raman scattering experiments. John did a very nice job of building a very carefully controlled ruby laser. The key, as I mentioned before, in any of these experiments was to get good beam quality in a solid state laser, and John did that by some very clever innovation, very effective Q switch which, very slowly opening Q switch which gave good mode selection, and then , with that good beam we were able to do some very nice stimulated Raman scattering experiments in hydrogen gas.

Bromberg:

I see, a follow-on from —

Glass:

— yes, I really wanted to do those experiments, because we wanted to show that if you really took a clean system, that you could analyze it and it was really amenable to calculation. People were still talking about (Illinois? a lot of noise?), and we published a paper in which we said, "Not only can you, does everything work out, you can calculate even where" — I was able to calculate the pulse shape , temporal pulse shape that came out of the Raman laser, and show that there were no anomalies, that if you did the right experiment, if you had a clean system free from other physics, that stimulated Raman scattering worked very much the way theory said it should. We were very pleased with that result. We showed that, for example, people had been looking at the anti-Stokes cone angles that Raman scattering, a Raman oscillator, if you set up a Raman oscillation, then the angles come out differently than they do if you just blast a laser beam into a Raman medium. And indeed we showed that the anti-Stokes rings came out precisely where we calculated they should, if you had a standing wave mode, an axial mode of the Stokes, as you must in a Raman laser. The Stokes wave now is traveling along the axis because it’s in a resonating mode, and that makes the ring, and anti-Stokes rings come in to a different angle, and they were exactly where we calculated them to be, very well defined. So we were very pleased with that result. About that time, John McCallum of ARPA and I were talking about, the French had developed this large glass laser, the of the Electricite, CGE, in conjunction with a glass maker, which was made by Corning, had set up — and I can't remember the name of it right now-they had set up an organization called CILAS, made commercial large glass laser systems, and we , John McCallum and I went over and toured the various European laboratories where these lasers were operating. We visited Culham, AWRE, in England. We visited Limeil Center for Nuclear Research and also Fontenay-aux-Roses in France. Came back, and then we had a big problem, because we had to get gold in order to pay for the laser. This was in the days when de Gaulle was not accepting dollars. He wanted gold. So we had to get gold out of Fort Knox to pay for the laser, which we did, and we got the first large glass laser into NRL, and that , we brought it over, set it up, and that technology, that glass laser technology developed by the French is still the basis of — that laser's still operating at NRL. We have one here that's still operating. There are bits and pieces of the lasers of that generation, 1967, "68, there are bits and pieces at Livermore, Mike Bass has one operating at USC which was originally acquired by the Air Force through their intelligence contacts, and was hidden away in various black Air Force laboratories for years, only surfaced on the surplus list, one at USC, without any of the manuals. Bass had to send his students here to find out how to turn the laser on. But anyway, so we brought over the first large glass laser, set that up, then shortly toward the end of my tenure there, John Emmett joined the group, and John subsequently added the first disk amplifiers.

Bromberg:

Now, who was the group at this point? When you came in, I assume you were going to build it up, recruit them fag people who were already —

Glass:

Yes, well, we had some people from within the laboratory. John McMahon was one of the mainstays. I brought in I guess Lou Sica, who is still there. Kolb was also doing some of the recruiting. He brought in, it was Kolb who recruited Emmett, John came in shortly before I left. Who else? Well, Bill Lupton I guess was part of the group, John Shipman, a number of people who were already at NRL. We brought in a few people from outside.

Bromberg:

They were all in Kolb's group?

Glass:

Yes. We also collaborated with the existing optics division, Lou Drummeter and Herb Rabin.

Bromberg:

Was this formally set up, as a special unit within the plasma physics, or this was?

Glass:

Separate. The way the Navy labs are set up, there are divisions, then there are groups, and the groups have sections and so on. We were a group. We were the laser physics group within the plasma physics division. So I reported to Al Kolb.

Bromberg:

Now, one thing that occurs to me...Ko1b of course was very much interested in fusion, and he's certainly a person that I think of as a —

Glass:

He had a — Yes, we had a big (crosstalk) experiment, Pharos was a theta pinch (?) machine, it was in the same building. Kolb was very interested in fusion, but at that time Kolb was already very heavily involved with Maxwell. Not long thereafter he went to work full time for Maxwell. Yes, we were —

Bromberg:

Is it right to think of your interest in fusion as —

Glass:

Well, I was interested in lasers. I was interested in the high powered glass lasers, and we were talking about lasers for fusion. I visited NRL, I mean Livermore a couple of times, talked to Ray Kidder. Ray had built the so called four power ruby system, which is a multi-beam ruby system, in an attempt to get spherical illumination of the target, and so there was a small effort going, but laser technology was so far away from what was needed for fusion at that time that really, one could only speculate, and the real interest then was an interest in developing better glass lasers.

Bromberg:

Kolb was, what about laser heating, was that an issue at this point?

Glass:

Laser heating of?

Bromberg:

Well, what I really mean is creating the plasma with it, you want for a magnetic system, was that ?

Glass:

Yes. That was being done at Westinghouse, and at United Aircraft, Alan Haught at United and lots of people at Westinghouse — and their names escape me now.

Bromberg:

Was that much of an issue with you people at NRL?

Glass:

It was — we were concerned with two things. We were concerned with the laser technology itself. We were also concerned with the development of laser scattering diagnostics for confined plasmas.

Bromberg:

OK, it was that whole field then.

Glass:

That was the primary interest. This primary interest among our magnetic fusion people, in terms of laser applications.

Bromberg:

When did begin recruiting you, or was that just incidental?

Glass:

No, Kolb recruited because he wanted to get a high powered laser group going here, but it was just a feeling, an understanding that that technology was something that the lab ought to know about. Fusion was a glint in people's eye. We talked about it but it was very far off.

Bromberg:

Kolb was also interested in laser simulation of weapons.

Glass:

Weapons effects.

Bromberg:

Weapons effects, yes, of course. I want to ask a little bit more about NRL, and then — well, no, reverting to NRL which we haven't quite finished, we talked about the experiments on hydrogen that you did there.

Glass:

Yes, Raman scattering, that's right.

Bromberg:

With hydrogen, and we talked about your getting the neodymian glass laser. I don't know if we covered sufficiently the other actual work that you did there.

Glass:

Well, we did an experiment. Ed McLain who was one of the people who was in my group, excellent experimentalist, we set up — Ed and myself — an experiment to observe the thermal blooming was being talked about, but no one had directly observed index changes associated with thermal blooming, so we set up an experiment in a liquid in which we did, we induced thermal blooming in an interferometer, so we could interfere and then we recorded the interferemetric changes, interferometric patterns on film, and we, that was very nice, because because we could follow the dynamics of the thermal blooming in great detail that way. That was a good experiment and we got a lot of information out of it. So we continued to look at thermal blooming. Of curse there was continued interest in thermal blooming in the atmosphere during this period, and a number of people were setting up codes to , you know, calculate the effect. I actually didn't set up a code, didn't really get into a detailed code analysis until I went to Hawaiian (Wayne ?) State, that's when I did that under an Army grant. I'll come back to that, because that code ultimately became Malaprop which is the laser design code of Livermore.

Bromberg:

Your name?

Glass:

Yes.

Bromberg:

Should I conclude then that ARPA's contract to you was also one of these sort of free form contracts?

Glass:

yes, the Naval Research Lab enjoys a very special, has a sort of privileged position, because it's a government laboratory. So funds that — they tend to have more latitude in how they spend their funds than industrial laboratories do. So we had a lot of freedom. I pretty much determined my own program.

Bromberg:

OK, because that is something that I — OK — so it was comparable to that TRG contract, you said, "go and think" or it was a little more restrictive?

Glass:

We submitted a work statement, and indicated what we'd be doing, that we'd be looking at these problems, but I don't recall worrying a great deal about the content, because I knew what I wanted to do. We didn't have any trouble writing a work statement and we would — it wasn't like a proposal, it wasn't like an unsolicited proposal, where you haven't been talking to the customer. We were, I was over at DARPA every week. So it was, the work statement evolved in the course of those conversations.

Bromberg:

Were you kind of a consultant to DARPA?

Glass:

Well —

Bromberg:

— after you left?

Glass:

After I left IDA, yes, I continued my association and NRL again typically, that's the role NRL plays with the various sponsors. They're not only doing laboratory work but they also have an advisory function, since they're in Washington and they're close by and they're government also so they're not — there's no conflict of interest, as a government employee you can sit on the government side of the table, and you can look at what the contractors are doing. I think it's a healthy situation.

Bromberg:

I should be ashamed of this, but a lot of this is very new to me. I have a feeling that Seidel already knows it all, but I certainly don't know it all yet.

Glass:

But, you know, a lot of it depends on personalities, too. I mean, I had worked with Sherwood and subsequently McCallum. We enjoyed a good relationship. People in DARPA, for example — you could have somebody in a laboratory somewhere that you could go to with problems, say, you know," So and so has proposed this, does it make sense? Can you find out?" Provide them with some technical support. They could get that from a place like IDA. They could get it form — I mean, that's why the Beltway Bandits flourish, you know, the contractors surrounding Washington, they provide expertise. But NRL has the added feature that they're a laboratory, you can go into a laboratory and find these things out.

Bromberg:

Yes, because DARPA is a group we think of as not having a laboratory, in contract to a lot of the other people.

Glass:

That's right.

Bromberg:

And what I didn't know is that NRL to some extent served as a laboratory for groups like DARPA. I think Bureau of Ships and so on.

Glass:

You see, we had no Navy money. I did talk to the Navy, talked to Chief of Naval Research, whatever, but, and of course we talked a lot to ONR, which is Navy research funding. But all —

Bromberg:

Did ONR administer your contract with DARPA? Or just direct contract?

Glass:

To tell you the truth, I don't know. I suspect it just went to the Naval Research lab, between the NRL and — because it was all within the Defense Department, I'm not even sure it was a contract. Funds were transferred. I really didn't worry at that time about those matters. I worried more about the technical.

Bromberg:

Well, that certainly explains a lot of the things that I — in glancing through your papers — the paper on design considerations for Raman lasers struck me as, I didn't quite understand where it fit in, but now what you've said, I understand very well where it fits in. Now, Wayne was a kind of a big change at this time, wasn't it?

Glass:

Yes. That came about for a number of reasons. I had, well, this was in the late 1960s, and I was a little uncomfortable with the being locked up sort of behind the fence of a military laboratory, even though we weren't doing anything military, and I'd always harbored a desire to be in a university situation, and a group of us, most1y from IDA, former IDA employees, discussed with Ali Shambel (?) who had been the head of the division I was in in IDA, Ali was going to Wayne State as dean of engineering and he wanted to set up a center at Wayne to attempt to apply modern technologies, well, to do two things — one, to bring some life into the engineering college, which was really in pretty bad shape, but secondly, to try to set up in an urban setting a high technology oriented center, and I thought that was a worthwhile idea. It appealed to me, and I thought it would be, I'd like to get involved in a broader range of things, and maybe make a contribution outside the realm of the military. So, as I say, a group of us went to Wayne, and it was as advertised. I mean, the engineering college was in fairly bad shape. But I enjoy teaching. I enjoyed the students very much. I had been teaching, I had been teaching at Catholic University, in the space science department. I got there. I set up a small laser laboratory, and I got a contract user at, in the Army, he was in the electronics command, he's now at Fort Belvoir to do some calculations on thermal blooming, also do some experiments, code work was the primary thing. So that was the motivation for going to Wayne.

Bromberg:

Really there is a real impact of the social climate in a sense, when you say it's the late sixties.

Glass:

Yes.

Bromberg:

It was the re-examination people were doing about military work.

Glass:

Oh, there was a tremendous amount, and there were people who had spent ten years with IDA and consulting with IDA, who suddenly appeared around here, "Power to the People" in student demonstrations. A lot of people were forced to examine their beliefs, and Vietnam. War could not be taken lightly and the social currents couldn't be ignored either. And that played — that, plus my desire to get into academic life — of course, that, like everything else, looks more attractive from the outside than from the inside, but those were the main factors that caused me to go there.

Bromberg:

I wonder if that had any lasting impression? Reading parts of this book, the STAR WARRIORS, by William Broad, I get the feeling that a whole new generation is now working which had no experience, real experience of the Vietnam War. I'm wondering if the experience that you people went through of re-examination is something which marks you off from this younger generation.

Glass:

Ask Peter Hinklestein, who's just left to go to MIT.

Bromberg:

Oh, did he? OK, I will.

Glass:

I think that would be very — and there may be parallels there, or it may be — you know, that's not a bad career track, to go off to a national laboratory where you have a lot of funds and you don't have faculty committee meetings to go to, where you can work hard and establish a good publication record, and then build up your credentials and go to a university position. That's probably a better way to do it than struggling up the academic ladder.

Bromberg:

After that Sock, he's probably going to be interviewed ad nauseum. Well, we were going to talk about the Code Malaprop.

Glass:

Yes. What happened was, I started to work on a code to model thermal blooming. Thermal blooming is a difficult problem because it's intrinsically a three-dimensional problem. The beam sloughs through the atmosphere, the wind blows across the beam, so the medium is transported across the beam, so you have to model the propagation, in one direction, you have to have the transport in a second direction, you have diffraction in a third direction , so there is no easy symmetry that you can take advantage of. You'd like to do codes in one or two dimensions. If you're in three dimensions, of course then ideally you'd also have to do it with time, now you're up to three space plus one temporal dimension, that's an enormous — So I wrote a code using alternating direction, implicit method, which is very efficient and very stable, and did some runs, showed some patterns, but in the meanwhile, other people I think within the defense community and some of the contractors had written better codes, people put in codes that showed the time dependency, but I just didn't have the capabilities to do that.

Bromberg:

I was going to ask about that. What kind of computer resources did you have at Wayne?

Glass:

We had a good sized computer, let me see if I know what it was. It was the same system that they had here at the University of Michigan at that time. It was like one step down from state of the art, which at that time was the 7600, national laboratories. So I could run — but yes, we had fair capabilities.

Bromberg:

I'm just wondering whether it was not a discouragement to even work on simulation programs of that sort, because you knew that the very best facilities were elsewhere.

Glass:

Well, the big problem was time, time, because I wasn't limited by the computer, I was limited by the amount of time — by that time I was department chairman, so I had a lot of demands on my time, administrative duties of the chair, I was teaching, I had students to supervise, and I had my own research. I'm sure you've heard all this before from every academic. So that was what limited me. I was in no way limited by the computer. And about that time, we were also going through some internal dissension at Wayne. I was only at Wayne for four years, but by the end of the time I was there, Shombell was fired, in sort of a bloody affair where a new president came in and asked all the vice presidents to submit their resignations pro forma, and then selectively accepted some of them, and so I could see, I felt the handwriting was on the wall, and also I was having some difficulties in my personal life at the time, so I had been out at Livermore on a summer assignment out there, and Emmett came in to set up a laser fusion program, this is in '72, and said, "Why don't you just come out here for a time?" I said, "Gee, you know I'm a tenured professor, department chairman" and so on and so forth, "it wouldn't make much sense," and six months later I was there, because the lure of the Livermore laser fusion department was just too great for me. It was such an exciting prospect, and something I really thought, really believed in, and it was just too good to miss.

Bromberg:

Just debating in my own mind whether to follow that through a little bit or go back and talk about Wayne.

Glass:

Well, we can come back to that if you want to talk some more about Wayne.

Bromberg:

Let's talk a little bit about Wayne curriculum and then I want to talk a little bit more about how Livermore fusion looked at that point. What was the situation at Wayne in terms of a laser curriculum, and what as far as you knew was the situation elsewhere? Were lasers pretty much assimilated by this time in terms of curricula, or what was going on there?

Glass:

It depended upon the presence of individuals. I think there were a few texts by that time.

Bromberg:

Probably Seaton's text was just coming out.

Glass:

Seaton's text was out, Reeves' books were not out yet. I basically created my own. I taught three courses, Introduction to Lasers, a laser physics course which was more advanced, and a nonlinear optics course. We used books like, what's that guy from — it's probably on my shelf — well, the name just slips my mind, but it was a very, it's the second or third edition, — anyway, there were sme standard sort of introductory books out — Lengyel, Bela Lengyel. His book, INTRODUCTION TO LASERS, I used that for my introductory course , and taught… and —

Bromberg:

Now, it sounds to me, though — were you teaching engineers? Or were these mostly physicists?

Glass:

That's a good point. See, I had taught physicists at Catholic U. I had taught both Introduction to Lasers and nonlinear optics, a course at Catholic U, and when I went to Wayne, I started to teach engineers. There's a profound difference. For example, teaching a laser course to physicists, you can go the whole course and never show them a picture of a laser. You can say, "All right, we start with Bloch (?) equations, etc." — write the equations, that's a laser. The typical physicist will be — this is not a unique observation from me, I've seen this actually documented in engineering education literature — with the engineer, I learned, I would start the course — SCIENTIFIC AMERICAN had a pretty good movie at that time about lasers and the first lecture of the course was the SCIENTIFIC AMERICAN movie, and we would go through, we'd do a section for example on the ruby laser, and we'd analyze it and talk about its special properties, and then we would come right back down to reality, and we'd show them a ruby laser. In teaching engineers, you have to touch reality much more frequently than you do with the physicists.

Bromberg:

What about the level of analysis? Would these people, by this time in 1970, did people in American engineering schools know enough quantum mechanics, or did you just go light on the quantum mechanics, did they know enough ?

Glass:

Depending on the level of the course. I taught a senior level course which really went very light on the quantum mechanics. They had to know that there was such a thing as a stationery state, they needed to know that much quantum mechanics. We used no quantum electrodynamics. But after all, lasers are such classical devices, in the electromagnetic theory part.

Bromberg:

And the electromagnetic theory was?

Glass:

Well, they're electrical engineers so they knew their Maxwell theory.

Bromberg:

OK, because education of electrical engineers is really changing a lot, from say the end of the Second World War on, there have been enormous changes, and I'd like to get a feeling, cut a section through time at various points.

Glass:

Well, one of the things I did as department chairman was I taught a number of — I taught courses in control theory , I taught the undergraduate electromagnetic theory sequence, and , because I wanted to understand what we were giving the students, and you're right, that whole electrical engineering was primarily driven by MIT — very strongly over to the aspect of controls, and got away from the more classical electromagnetics, certainly power option (?) almost disappeared in many schools. But no, I found that the students had adequate electromagnetic theory. They could learn, at least they could learn to accept that there were such things as discrete states in atoms, and you get the atoms out of the picture very quickly, just talk about gain and they understood gain, so that was at the senior level. I also taught the advanced course and the nonlinear optics course at the graduate level, and there, I didn't have many students but I pushed them to understand quantum mechanics and we used the density matrix formalism.

Bromberg:

Where were your students going when they left Wayne?

Glass:

Several went to Livermore. Two, three — four — four of the people who either took courses from me or did graduate, did thesis study, thesis work with me, are now at the Livermore program.

Bromberg:

This was a sizeable Ph.D. program?

Glass:

No, we got — in fact, fired more Ph.D. students than I hired. We had a Ph.D. program going but it was a bad program, and I told a number of these young people, "You're much more employable as a good Master's degree student than as a bad Ph.D." The world is not crying out for bad Ph.D.s. And these guys could be first rate engineers but they were not first rate researchers. So we shrunk it down, in fact, we had — well, what we did was, we set up a group called Research Institute for Engineering Sciences, which was drawn from all departments in the engineering college, and so, we didn't have a large pool of graduate students. This was a way of concentrating them, rather than having one student in mechanical engineering, another student in electrical engineering, and that worked pretty well, and as I say, there were about ten people who came into the faculty at the same time I did or shortly thereafter and formed a nucleus for change, and that worked very well. Several of us went on to become department chairs, ultimately deans, some. So it had a good effect on the college. We never achieved the level of, the degree of improvement we wanted to. We certainly didn't do much in terms of broadening the application of our technological interests to broader social issues. We did, we started to look at urban issues, transportation, energy, etc., but we really didn't know the politics of those programs, and also the politics of the university, which created problems in your own field.

Bromberg:

That's a whole interesting subject which I think I’m not going to try to go into because I'm charged to do laser, but it would would be very interesting.

Glass:

The other thing I did which was an interest which I've subsequently pursued here is, I did set up a bioengineering program, and that was a great interest to me, and —

Bromberg:

Now, what was the precedent for that? Was that just de novo when you set that up ?

Glass:

Yes. Adrian Kantrowitz, Arthur's brother, had come to Detroit, and is still there, at Mt. Sinai Hospital, and he had an excellent, small but excellent group. A fellow named Dov Jaron, who is now at Texas(?)was his chief bioengineer, and I made Dov an adjunct professor in the department, and spent some time , put some joint proposals together, and also did some teaching in the medical school as a way of sort of building a bridge between engineering and optics to the residents in ophthalmology.

Bromberg:

Where did your own interest in bioengineering stem from? Is this something that was developing already?

Glass:

I'm not too hard to get interested. I'm very interested in Biotechnology — I think you're still plugged in there — I'm still interested in biotechnology. It just —

Bromberg:

Was it laser, lasers of course have obvious bio —

Glass:

Well, that was what started me off, because people were concerned about laser effects in the eye, of course. Bromberg : That was an ARPA concern, wasn't it, range finders?

Glass:

Yes. That's right. That was already starting at the time when I was at IDA. People were trying to find, shift the operations of the lasers out to the eye safe region, that was another motivation for being interested, in Raman scattering —

Bromberg:

— oh, I didn't —

Glass:

— to shift glass lasers out to where they're eye safe.

Bromberg:

Did that pan out?

Glass:

No, because again, urbium (?) and homium(?) lasers were developed. It was again more efficient to fund a new IM (?) than it was to downshift the glass lasers. Because it doesn't, the Raman effect is not very efficient, as you move out into the infra-red, because you lose, you give up half the energy of every photon, so — it's a heavier price than you want to pay.

Bromberg:

Let me just get an estimate, though. How big, you say that was one of the motivations, can you give me some feeling for how big that loomed in the whole brew, the idea at IDA that this might be one of creating eye safe lasers, and how big the whole question of eye safe lasers was, just to get a feeling for —

Glass:

It wasn't a really, it wasn't a big concern. It was more, I think it was more a concern of the services than it was of ARPA, because after all the services have to do the training. That's what you worry about, you worry about injuring your own people in training, and I think it was more a concern of the services, and it was just sort of tossed in as an added feature of Raman scattering, but it was not the primary motivation. The primary motivation was to clean up bad beams, improve beam quality, enhance brightness for strategic applications.

Bromberg:

All right, from another point of view, how formative was this interest in eye safety for your own getting interested in aphthalamaic (?) —

Glass:

I was just interested in general. I became interested in bio technology, in particular from listening to lectures from our resident biotechnology people. There was some biomechanics activity going on within the college, which really came out of crash studies, automobile crash studies, and which had been going on for some time, and so that got me somewhat interested, and then the realization that bioengineering involves the application of engineering, the engineering approach, engineering analysis to biological systems. When I realized that, I said, "Gee, that's very interesting, and it seems to me could really be very fruitful. "So I think really my interest came into maturity at Wayne State, from just talking to people, listening to the things that people were talking about. We had a very active colloquium program and brought speakers up, because we were trying to — a group of us had come from primarily defense related activities, and we were trying to see, where else can we apply our expertise, in non-defense areas?

Bromberg:

It would be interesting to see whether these fields actually ...

Glass:

... disappeared as a concern, and strategic defense is coming in.

Bromberg:

I think that really just —

Glass:

— this doesn't have to do with lasers but you might be interested. At the time of the Cambodian incursion and Kent State hootings, I was teaching an honors course on technology and society at Wayne. It's the best course I have ever even either taken or taught. To my mind it was one of the few, probably the only time I'd ever realized what I think college education ought to be , because first of all, the honors program was selected from the top like 2 percent of the students, undergraduate students at Wayne, so I had the first requirement of good teaching which is bright students, and it was a subject that I knew and had thought about and lied through. We talked, we used Greenberg's book POLITICS OF PURE SCIENCE, it's a rather textbook primary reference, fairly extensive reading list, and in the middle of the — see, we were just getting into the business of how the Defense Department influences science, when Kent State shootings occurred and the whole campus was in an uproar, and the students took over the administration building, as was the custom in those days, and declared a free university, and mine was the only course accredited in the free university as well as in the regular one.

Bromberg:

What an honor!

Glass:

So I put together a symposium on the military influence on science, and I had former ONR guy who was on the faculty, I went around and sort of found people with government experience, and we had a pretty good group of students listening to us, and having the discussion. And somebody said, "Excuse me, could we move to a large auditorium because there are more people who would like to hear the discussion." Well, no professor can resist that, you know, so we moved to a larger room and I got up and sort of reconvened, and somebody said, "Sit down, you're not in charge here." We are now in the kangaroo court, and were put on trial for war crimes. That was an interesting experience. We got out of it OK. I don't think I was acquitted, but they, the student newspaper published my CV in red, white and blue, and you know, Army service and so on, but it was very, it was really very interesting, because you got a chance to — one was forced to explain the rationale. Why did you do it ? Why did you make those choices? Why are you doing this? Why aren't you doing that ? So it was impossible to go through that era without really giving some thought and scrutiny to what you were doing.

Bromberg:

I think that's well worth taping...

Glass:

That was a very interesting time, and I must say I learned a great deal. I learned in particular dealing with angry mobs in our research institute which was invaded by the students, and we were just putting together a big proposal to the National Science Foundation, and the proposal was sort of sitting around, it was being collated, and I was concerned for the safety of the people working in the office, and I was concerned with the safety of the proposal. That was a month of work. And these students broke in the door, and I was very foolishly standing in the doorway trying to hold them back, and I remember, this one woman was hanging on my arm, kicking me, screaming at me — so we were having a fairly earnest discussion at this point, when the people at the front of the crowd came surging in, and I realized that if you could talk — if you talked sort of past the — there were some people standing just screaming, and if you could sort of talk past them and get the more reasonable people — And the students realized that they were very threatening, and some of them hadn't realized it, and one of them said, "Well, you've got to go home. Shut this place up and go home." And I said, "Fine, when you leave, we'll do that." And they said, "Why?" And I said, "Because I'm concerned about the safety of these people." And this one kid said, "What are we going to do, rape somebody?" And I said, "I don't know what you're going to do." And you could see on his face, he hadn't thought about that. He hadn't thought how threatening a mob is. So there was a pretty good dialogue going on, and I think in that week or so, we did more teaching than we did in a year of normal circumstances.

Bromberg:

Now, I'm going to just let that stand as background, because I do want to ask, first of all, in bioengineering, were you also in contact with any of the medical laser people at this time, for example, the people down in Cincinnati or maybe local, I don't know?

Glass:

Only from time to time, I would try to keep up with what people knew about laser safety, eye safety. But not really in any significant way. I wasn't primarily concerned with lasers for bioengineering.

Bromberg:

OK. Now, all during this time, besides the Malaprop Code, or maybe as a part of it, you were also working on laser damage.

Glass:

Yes. That was really a separate activity. That came about, and that's something you wanted to talk about and this is a good time to talk about it, in 1969, the National Society for Testing of Materials decided they would set up a laser standards committee to try to develop standards so that when people talked about power and energy and other attributes of lasers, there'd be a general understanding of what the terms were. Guenther, I think, was asked to put together, to chair a group, and they asked me if I would participate, so — and I was also by the way consulting at this time with Owens Illinois on glass lasers — So Art and I co-chaired a meeting, we held it in Boulder, and we thought we'd have a one day informational symposium, just to get some information before we sat down and thought what we had to do the NST, and that was the first NST damage symposium . At the end of that meeting, we recognized that there was a whole lot more to do, but that was how it got started.

Bromberg:

Now, I can't help believing that it wasn't just the ASTM, that there must have been other groups involved. Were you involved in the origins any more than just Art invited you to be on the committee, or were you just a guest?

Glass:

There were several of us one the committee, people who had an interest in high powered lasers, and I don't remember the, without going back to the notes, I can't remember the full composition of it. But then we put this symposium together, a one day meeting, and a lot of people showed up, from all walks of life, as I say, and —

Bromberg:

Was that a surprise, the amount of interest?

Glass:

I think it was a surprise. I think we started off thinking we could have a one day meeting, and get some things defined, clarified, and maybe then write some standards, but by the time we got done putting the meeting together, given the interest of the attendants, you know, we saw there was a lot more to this, so we said, we're going to have to build up a team to work on this, so we then this became, we went back to the AST and also got some support from ARPA, and ultimately from the Department of Energy, and some support from the Air Force, and on and on, and it was clear that there was a broad base of interest in this, and so we put together this symposium.

Bromberg:

Now, all this time, of course, you had a windows group, didn't you, under DARPA? Windows damage? I have a note here — In '76, yes, Martin Stickley —

Glass:

Yes, Martin was in charge of materials program, materials

Bromberg:

How did his materials program relate to the major damage symposium?

Glass:

I can't remember exactly what it was. I'd have to go back and look at the damage symposium PROCEEDINGS, but there was a point where we began to hold the meetings in coordination with the windows meeting. The windows meeting was classified. So we would have like, the ASTP damage symposium toward the end of the week, and then pick up the next week with the classified meeting, or we held the classified meeting in the first couple of days and then the damage symposium, because we wanted to keep the damage symposium unclassified, international, because we were getting Soviet participation.

Bromberg:

Yes, that was one of the things I wanted to ask you about. What was the, what were the foreign groups which you were most in contact with on the whole business of laser damage?

Glass:

Well, the Lebedev Intitute, Alexander Manenkov,in Poporov's group at Lebedev. Manenkov has attended several of the damage symposia meetings, and Faizulov. So that was the primary group. We had, the French were more active in laser development. We had representation from CGE and from the men. Various English groups, English scientists were involved. There were others. I think in the thin film area, we may have had — we did have some papers from Germany and, I can't remember Balzers ever showed up or not, but in any case, the primary groups were the ones I mentioned.

Bromberg:

Let me just get this a little bit resolved over time. So the Lebedev people are going to be a constant feature right straight through from ‘69 on?

Glass:

Well, not in ‘69, but early seventies, certainly. Manenkov began to come to the damage symposia.

Bromberg:

And so if we go say up to 1980, we still find a fairly —

Glass:

I think he was, maybe the last one or the one before that.

Bromberg:

OK. And you say the French, there was a kind of a peak.

Glass:

Yes. They are less interested in high power, they have less high power activity.

Bromberg:

So when did they flourish?

Glass:

Mid-seventies, I'd say.

Bromberg:

And then the German group, is that something —?

Glass:

Well, that would be more individual scientists showing up, and there have been, oh, there have been Scandinavian scientists, —

Bromberg:

How come you didn't mention the Japanese, which I always think of as one of the important groups? That wasn't an important group?

Glass:

I don't remember significant Japanese participation.

Bromberg:

OK.

Glass:

Not true, that's not quite true. Hoya Glass did participate, yes. Yes. Dr. Izumatani was the director of research at Hoya. Yes, he did participate.

Bromberg:

Now, should I understand that your role in this is as a symposium organizer, or is there some larger role that you were also playing in overseeing laser damage?

Glass:

Well, I wasn't overseeing it. During the time I was at Wayne State I was consulting with, my activity was primarily through the medium of consulting with Owens Illinois on laser glass. Subsequently when I went to Livermore, then I was directly involved in all aspects of glass laser design. In terms of the symposium, I was co-chair and organizing chair of the — chaired the job of organizing the meeting, and we organized the meeting and invited the speakers. We had a secretariat provided by the Bureau of Standards, but we — and we then edited , read all the papers, transcribed the discussion, edited the PROCEEDINGS — a lot of work. It took a lot of work. I used to spend — well, it totaled about one month a year , not all continuous, but over the course of a year, a total of about a month involved, which wasn't all bad. Then when I came here, actually, yes, I dropped out of the field when I came here, because it was just that type of outside time commitment was inconsistent with my duties here.

Bromberg:

The reason I was asking that was, I wanted to ask about the — what you saw of some of the leading programs. China Lake was one that I understand you had some role, even in the origins of their laser damage program.

Glass:

Well, I don't know whether I had a role there.

Bromberg:

This is information from Seidel.

Glass:

They submitted a proposal — of course, Hal Bennett had been involved in laser damage — both the Bennetts had been involved in laser damage studies from the start. Not so much from the damage point of view as in terms of the characterization of surfaces. Jean (Bennett) in particular had done much more in characterization of surfaces, of scattering and so on. Jim Porteous and Terry Donovan and others had done some work on mirror damage. So they were fairly active. While I was at Livermore, they put together a fairly large proposal, and that kicked around — quite frankly, I wasn't, I mean , it wasn't a proposal directly to me. I think it was to DARPA. It wasn't to Livermore, it was to DARPA, or to some aspect of the DOD, for support. I remember looking at the proposal from the viewpoint of, — there was a lot of pulling and tugging as to who would be funded to work in the laser damage area, and as I say, I wasn't in on the final decision, but I do remember a certain amount of controversy as to whether, to what degree China Lake would be funded for that. They certainly had been one of the main players in the laser damage business. Mike Bass of course at USC.

Bromberg:

Yes, they were also a group, weren't they?

Glass:

Bass?

Blomberg:

Well, I think of Bass and John Marburder and —

Glass:

Yes, those guys were very strong contributors to the damage PROCEEDINGS, until Jack got into university administration. He had typically attended every year, he and his students, and Bass was active right from the start. From Livermore, Dave Milam, who had actually gotten involved in this field working with Martin Stickley at CRL. Back in the late sixties. Martin and my old Washington. Bromberger: Now, Seidel sent me a little bit of information on a meeting, not a meeting but an IDA study in 1970 that was Walsh and Axzmuth(?)and Milton were head of it and I don't know exactly how you participated, and he said that it reached a number of rather interesting conclusions, both in terms of technology and in terms of institution. It played with the idea of a national laboratory devoted to laser damage, and the politics of, you know, setting that up in a period of budgetary constraints, and discussed other ways in which the government could strengthen its laser and nonlinear optics materials capabilities and identified a series of program objectives, high average power capability, development of isolation techniques to prevent Q switch neodinium YAG lasers from lasing prematurely — a whole host of things, and I would like to ask for your memories of that whole —

Glass:

I had nothing to do with that.

Bromberg:

Well, in that case you don't have any memories.

Glass:

But let me say that two proposals have floated around for 20 years. One is to have a national laser laboratory, another is a national center for laser damage studies, and neither one has ever taken off. And I think that's because, there's a deeper truth hidden behind that. Things don't get funded in this country unless there's a program. A laboratory to develop lasers for their own purposes, for their own justification, doesn't develop any enthusiasm. Laser damage as a study, apart from an application, is seen, and probably rightly so, is seen as a sort of an exercise in omphaloskepsis, that people will just — John Emmett put it very well one time, when we were talking. I was on my way out to the damage symposium. He said, "Why don't you tell those guys to find ways to avoid damage, rather than to understand damage? "And in fact, that's, in the laser fusion program, what we wound up having to do.

Bromberg:

I see.

Glass:

That is, you get to a certain point where you say, I don't fully understand all the aspects of damage of optical surfaces, for example, but I know empirically that I have to keep the fluff belong a certain level. That's all I need to know about it at that point.

Bromberg:

It's kind of an engineering versus a physicist's —

Glass:

Absolutely. And the people who are interested in laser damage typically are people who are dealing with high powered systems, or at least high power density systems, and I add that caveat because optical fibers, people in semiconductor lasers and optical fibers try to jam as much power as possible through a small surface, and they run into optical damage problems too, but the primary motivation for funding certainly has come from the people who want to build big lasers. They don't want to understand laser damage, they want to build big lasers. And that's why I think that proposal probably fell on deaf ears.

Bromberg:

This comes through as a kind of a thread through, this interest — what does it go back to? When does it first surface?

Glass:

I heard people talking about a national laser laboratory when I was at IDA, 20 years ago.

Bromberg:

Is this a particularly strong thing that's going on?

Glass:

No, I don't think — now, —

Bromberg:

This is a current in laser thought that I have never come across. I want to know —

Glass:

Is that right? Well, the proposal surfaced several times in the late sixties, early seventies.

Bromberg:

Mostly within DOD?

Glass:

Well, as soon as Livermore got going on the laser fusion program, in Livermore's collective mind and in John Emmett's personal mind, Livermore [???] the national laser laboratory. And in many ways, it is. They have broadened the program to include the development of new solid state lasers, to include a certain amount of laser damage work, to include the improvement of sources, all aspects of technology, and so on, and so on. And so I think right now, I think that's one of the reasons why since the mid-seventies one hasn't heard this proposal any more, it's for that reason, that de facto a national laser laboratory exists.

Bromberg:

OK, but if I do look for this just as a thread, it would be within the DOD?

Glass:

DOD, yes, it was DOD.

Bromberg:

Let's get back to talking about you’re going to Livermore. Now, a big change takes place around '72 in the Livermore fusion program. They got a lot of money. They got John Emmett.

Glass:

They got Emmett, yes. Carl Hausmann got the money.

Bromberg:

I see.

Glass:

And then went out and hired Emmett. Hausmann had, Charlie Rhodes and Bob Carman were — and Ray Kidder — were the sort of — they were the people who were driving the laser program at Livermore.

Bromberg:

A constant funded program, as I understand it, about a million a year.

Glass:

Yes. I don't know what the funding was. I wasn't associate with it, but that doesn't sound unreasonable to me. And then, in the early seventies, Carl, for a variety of reasons, and I don't know all the details, Carl Hausmann became convinced and was able to convince, I think it was General (Alfred) Starbird in DOE that — head of military applications, in those days in the AEC — able to convince him that the time was propitious to build a big laser to do laser fusion. And the, they asked I guess Charlie Townes and Teller was involved and so on, who would be the best person to get, and Emmett was the choice, and Emmett was a very good choice. John's just a superb engineer/scientist. The lasers that have been built at Livermore, I firmly believe no one else could have built those lasers but John. John didn't do it single handedly, but it took a combination of technical knowledge and management acumen and just leadership that, and personal traits, ego — that John uniquely exhibits. So they made the right choice. So John came in. I was there when he and (William ) Krupke arrived on the scene. I was out there for the summer as consultant to Bob Carman.

Bromberg:

Do you remember what summer that was?

Glass:

Sure. That would be the summer of '81, was it? Let's see.

Bromberg:

‘71?

Glass:

Pardon me, ‘71 ‘66, ‘68, then ‘72 — I left , I joined them sort of in March —

Bromberg:

— ‘73, didn't you?

Glass:

Was it?

Bromberg:

Yes, it's got you down there as going to Livermore in '73.

Glass:

That's right. That's right. So I was there in late 72, and that's when John came. Late ‘72.

Bromberg:

You were there in the summer of 72.

Glass:

I was there in the summer of ‘72, yes. And then I came back full time in ‘73.

Bromberg:

So what was going on at that point? This was a transition, I would think.

Glass:

Well, what was going on was, even by Livermore standards, was a bloody battle. Livermore has been the scene of many bloody battles. Any organization of which Edward Teller is just one of the associate directors is an interesting organization, and Livermore is famous for it’s — for the internal politics. But this was bloodier than most. John had very clear and definite ideas what he wanted to do. He wanted to build SHIVA, and there was opposition from — there was a — first of all, there was a real battle between John and Ray Kidder. Ray had been the guru of laser fusion there. He was ostensibly, according to John, he wanted to build a different laser than the one John wanted to build . He wanted to, I think, spend more time on some of the intermediate physics questions, and John was saying, "All our physics is irrelevant to getting a laser big enough to do something." There were, John — well, John brought with him John Trenholme, who is a superb analyst, and had developed while at NRL a set of computer codes that enabled him to analyze the performance of solid state lasers better than anybody else could, particularly the pump cavities, so John had a sort of a personal staff to back him up. Ray, who is a wonderful guy, super physicist, had surrounded himself with relatively weak people, and there was an infamous shootout, and I don't remember the day, but it was held in front of Teller, in Teller's office, where Kidder and Emmett went toe to toe, or mano a mano, I guess they say, as to who knew how to build a glass laser, and Kidder was, had been poorly prepared by his staff, and came out a very bad second best. And from then on it was — that solved that issue.

Bromberg:

…the decisions on, you say that the —?

Glass:

It was really — I don't know. I don't know who made the decisions, but I know that Teller — my memory is that that discussion was held in Teller's office, and that he was the arbiter. Teller was instrumental in bringing John to Livermore. He was instrumental in advancing John at Livermore, and of course now he's not John's greatest supporter by any means.

Bromberg:

Who else was important in the administration with the fusion program? Was it a big enough program so that everyone had to be important? Hausmann was associate director at that point, wasn't he?

Glass:

Yes, but Carl was really the, as they say in the Air Force, the Daddy Rabbit. He was the guy who cleared the path for John. Carl is a very astute technical manager, very knowledgeable in the ways of — in the political ways of Washington. He, John learns very quickly and is very acute, so between them, they built a very, very good support in the AEC , subsequently in DOE. And they also built a very good support in the Congressional committee on atomic energy. But Carl was the — Carl cleared the way for John, cleared away the logjam.

Bromberg:

He was in administration.

Glass:

Yes. And of course Roger Batzel was a strong supporter too.

Bromberg:

Now, I think of your work at this point as going into, both the areas of lasers for fusion and also continuing in laser damage, is that right?

Glass:

Well, I went to Livermore, I had a mandate , I started off, John asked me to come in and run a basic research group, a sort of a thing called advanced studies or something like that , but after about a year, year or two, it became clear that that wasn't working. And it wasn't working because , sort of , from a standpoint of science management it's sort of interesting to know this — two conflicting tendencies. One is, our group, it was like a little university group with the laser fusion program. We didn't have the kind of urgent milestones and time pressures that the guys who were building SHIVA had. Or the predecessor systems to SHIVA. So we were viewed somewhat enviously from within the program, as those guys have carte blanche, they can do whatever they want, they don't have to meet any time tables, it's a a sandbox. By the same token, people within this group felt that the urgency of what the lab was trying to do, what the Y division was trying to do, the laser program, that — you know, gosh I really can't just go off and think about academic matters, I really want to get out there and help with the fusion laser. So after a year ago, as John and I talked about we agreed this isn't the right way to go, tht it really didn't make sense to try to run an existential activity within such a goal-directed activity. So I redirected my efforts. I took my own responsibility for the theory and design analysis, as it was called, which was really two things. One John Trenholme, John Hunt, myself, supported by some excellent programmers and analysts, began to put together a library of computer codes that would be needed to design SHIVA, and I dusted off Malaprop, my old thermal blooming code, made some changes on it and so on, and we reinstated it’s a propagation code, to study propagation through the glass laser systems, and I built into it the nonlinear optics, and I also put in some statistical sources, some random noise generators, because there are certain phenomena in a glass laser system that you can't model causally. Beams break up, but the origin of the inhomogeneity, if you will, the fluctuation in the intensity of amplitude and phase arises from multiple scattering processes at various surfaces and so on. So what I did was, I just put in noise generators, and I could tune the spectral , the spatial frequency spectrum of the noise, the amplitude and so on, and power spectrum of the noise, adjust that, and we sort of played around with those noise sources until they seemed to be consistent with what we were seeing in the laboratory, and then we were able to scale up to the larger system.

Bromberg:

Was that still called Malaprop?

Glass:

Yes, Bill Simmons — it was still called Malaprop, and it is still called Malaprop, although it's no in its third embodiment, because Bill Simmons, who has now subsequently gone to TRW, Bill took over the code when I left, and he modified it, because we were out of the design phase and he wanted to do more modeling of the system as it existed, took out some of the problems that seemed important when I put it together, and changed it so it's now sort of in its third lifetime, but it's still called Malaprop.

Bromberg:

There are a number of codes whose names have passed through my head. They have to do with the laser at Livermore, and so I'm assuming that you were not the only group that was working with codes?

Glass:

There was Joe Flack, in the theory division. We asked him to develop a code. He was a very good code builder, but the problem there was, he wanted — the standard formula — he wanted to go off, work for a year, come back, say, "Here's the answer. " Well, we needed a code yesterday. So John Hunt developed a code called I think Artemis. Trenholme had a lumped element code, out of which he developed what's called the B Integral, which was the cumulative phase distortion, very important for beam breakup. What we're talking about here is just self-focusing writ large, I mean, I'm talking about the phenomenon by which the beam breaks up when it passes through a large glass laser system. It's precisely self-focusing, but whereas self-focusing as Townes did it was in tiny little beams where y ou saw it in intense form, this was done in very large beams. And now it manifested itself as an instability, and the fact is that the surface, which starts off as a nice uniform phase surface, breaks up into a myriad of filaments, and then it can't be focused. So, that is parametized by the integral of the nonlinear phase distortion along the beam path, and that's what Trenholme called the B integral, and that was a very important contribution. The two most important contributions that came out of that group — so I had Trenholme, John Hunt, several other people working for me. We were developing a family of codes to enable us to design large glass laser systems and monitor performance. At the same time, I had a group of people, including myself, working on the analysis of nonlinear optics phenomena, in particular, I did a lot of work on what are the origins of the nonlinear index, and how can you predict what the nonlinear index will be from the linear properties ? And we developed an empirical relationship which worked very well. So then you see what happened was, in the course of this work, Trenholme as I said developed this very nice formalism to, so we could, in terms of a single parameter, we could sort of indicate whether our laser beam was going to break up or not, and that was very important. The other thing is, John Hunt came up with a brilliant idea, which was a way to defeat self-focusing, and that's the so-called Hunt relay scheme, and until he did that, there was an absolute limit to the amount of energy one could extract from a single laser beam.

Bromberg:

When was this, about?

Glass:

Mid-seventies, maybe ‘74.

Bromberg:

Did that have a big effect on the direction of what you did?

Glass:

Yes, it meant that we could build SHIVA with far fewer arms than we thought. It meant ultimately we could NOVA at a hundred kilojewels with ten beams. In 1972, there was a laser meeting in Montreal. John Emmett gave a paper. He said, " The maximum energy you can get out of an arm of a beam, one arm of a laser, a glass laser, is a kilojewel." So if you want to build a 100 kilojewel laser, it would have 100 arms. Well, Hunt showed how you could make that , I mean NOVA ,as 10 kilojewels per arm, and in fact, you could go even further, so it was a tremendous breakthrough in glass laser development.

Bromberg:

Did it mean that you stopped working on self-focusing problems or theoretical or —?

Glass:

No, we continued to work on — because all it did was, it's like curing someone of a disease, that is, it only postponed the inevitable. We still had — it simply extended the limit much further, and we were still very much concerned with attempts to find optical media with lower nonlinear indices. A very big payoff for that, and Marvin Weber and I worked — Marv was funding a lot of work on new glass compositions and so on, and I was doing the analysis, and we predicted that phosphate glasses, for example, would be much better than phosphate glasses which in turn were Much better than silicate glasses. Unfortunately, by the time Nova had to be built, filer phosphate glasses still could not be manufactured in large enough quantities.

Bromberg:

In a group like that, do you do all the work within the group, or do you actually contract out?

Glass:

We had outside contracts. We had people within the group doing work, working for me, I had my own work.

Bromberg:

Was there a contract that was particularly important that we should note here, any groups?

Glass:

I'm trying to think back — Interestingly enough, we did some work simply, I mean, without contract we did some collaborative work just because people were interested. I worked with Norman Bolling, who was at Owens Illinois, and Del Owyoung who was at Sandia, and we just sort of got together because we were all interested in the subject, and worked up this empirical theory which ultimately was used as a way of predicting what the nonlinear indices of glasses would be. I don't think, in terms of — well, Marv Weber had a lot of contracts with various glass makers to try to develop low index laser glasses, but I wasn't directly involved in that .

Bromberg:

Now, I am very concerned with some of the many ingredients in the program that you had through ‘78, and optical compression techniques had a role in here, didn't they?

Glass:

Well, when I first started out there, Emmett gave me all the problem children, to manage, including Bob Carman and a guy named Bob Fisher, who subsequently distinguished himself in the field of phase congregation. He's now at Los Alamos, where he's very highly regarded, does very nice work, very highly regarded. At that time Bob Fisher was particularly interested in the Gires Tournois interferometer, which is basically like a Fabry-Perot and he, it had been touted as a scheme for pulse compression. Remember, we were still trying to find ways to compress pulses, at this time, control pulses. Because if we could use lasers, other lasers, not necessarily glass but other lasers like the exomers (?) or whatever that one had to generate energy at longer pulses, and then compress the pulses optically, then that would be better. Even glass lasers are more efficiently operated than longer pulses. Well, I did an analysis and looked at the Gires-Trounois and concluded that it was not a practical means of pulse compression. In fact, I published a paper that said that there was a limit on how much you could compress that way. On the other hand, there were other schemes, of grating pairs, for example, that looked rather good, and subsequently have been demonstrated to be very effective in pulse compression. The problem is, all schemes work in taking a one, a 10 peak a second pulse down to 100 femtoseconds? They don't help you go from 10 nanoseconds down to a nanosecond. That's where we need pulse compression. So the optical tricks, which all really amount to using varium (?) path lengths and so on, they don't, they didn't work in the regime we wanted them to work in. They've been used subsequently to get these ultra-short pulses, but that didn't help us. So that was my involvement with pulse compression.

Bromberg:

Now, I have a feeling we didn't really cover what was — but it's now 11 — and I did want to ask at the very least about the fusion review group in ‘78.

Glass:

Oh yes.

Bromberg:

Why don't we talk about the fusion review group, and then if we have time, which I don't think we have, we can —

Glass:

OK. Well, what happened was, in 1978, John Deutch was the Assistant Secretary for Energy Research. Schlesinger was the Secretary of Energy. And Deutch wanted to know whether or not he shouldn't just kill laser fusion, in fact, fusion in general, just — he was very skeptical about the prospects for fusion. So he convened a panel, headed by Johnny Foster, to review the fusion programs. They asked for staff support from the national laboratories, and I was asked, they wanted to get one person for magnetic fusion and one person for inertial fusion. I was asked if I would be interested in the inertial fusion. John Emmett and I had been talking about the fact that I had just about completed the objectives of the design group. We had finished. We had our design codes. We had not solved the damage problem but we knew how to get around most of the problems. It was time to move on to something else. So it was an opportune moment, from my point of view. Unfortunately I had just gotten married, and it was not an opportune moment in my personal life, because my son was living with me, and it meant that I would be back in Washington, and my son would be living with my new wife, and his whole purpose in coming out to California, my ex-wife was living in Connecticut, his sole purpose was to be with me, and so we agonized over it, but finally I concluded that I should do it, and so I went back. Mike Roberts from Oak Ridge was the fusion person, he's now deputy to John Clarke in the magnetic fusion program in Washington. So Mike and I and — we were supposed to provide sort of technical staff support to the Foster Committee. We sat in there on the Foster Committee's hearings. We helped write the final report. We did legwork, we —

Bromberg:

Of course, you were both advocates, weren't you?

Glass:

Yes, we were.

Bromberg:

Did they have anybody there who was on the other side, who would —

Glass:

Tom Johnson from —

Bromberg:

IBM?

Glass:

No, Tom was head of the Science Research Center at West Point —was hired really by Deutch as an inside man to kind of provide Deutch with another viewpoint on what was going on, and Tom was also very, very accomplished raider (?) and Johnny Foster has a great deal of confidence in Tom, so Tom was providing a more objective viewpoint. I remember when Deutch interviewed me. He asked me about bias, he said, "Do you feel you have a bias ?" and I said, "Yes, I feel I do, not only because of the work in laser fusion but because I've been at Livermore and there's a Livermore style, and I know that I've absorbed that style. "But it was all right. There were plenty of detractors, to balance out the advocates. But it turns out that both the magnetic and the inertial fusion programs made pretty good impressions on the committee, and the report that came out was really very positive, so much so that it convinced Deutch that he — it turned him around. I mean, I think he started off feeling that he wanted a report that would enable him to recommend the termination of the program.

Bromberg:

I was going to ask about that. How much do you think Deutch was controlling that committee, and how much was it ?

Glass:

It was not a committee you could control. Johnny Foster, this guy from Bell labs, Sol Bucksbaum, John Simpson who had run the nuclear program at Westinghouse — I can't remember, I don't think Davidson was on it — but in any case it was a very senior committee. The way you control a committee like that is by selecting it. You can't control it once you put it together. Those people have to — they didn't have people who could be pushed around. As I say, Deutch —

Bromberg:

The selection?

Glass:

The selection process is always very, very political, and the panel was a relatively skeptical panel. People with a lot of experience in program management, government programs, people who knew their way around the national laboratories, weren't easily buffaloed, although the labs do a good job of buffaloing people , but they — these were people who at least knew they were being pushed around by the labs. But in any case, no, it was a pretty good committee, and at the end, we went in with a presentation to Deutch, which he took to Schlesinger, in which we said, these programs are good programs, let's keep them going.

Bromberg:

Thank you very much.