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Interview of Peter Franken by Joan Bromberg on 1985 March 8,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
First acquaintance with the laser idea in the late 1950s; rejection of Theodore Maiman's paper by Physical Review Letters; Trion Instruments; nonlinear optics researches; clear-air turbulence experiments; role in the Fordon Gould patent cases.
Well, shall we go to the questions?
Yes, I think so, and then we can digress as it seems useful.
It’s hard to stop me from digressing. OK, “how well acquainted were you with lasers and masers before 1961?” Not a great deal with masers. I certain was around Columbia at the time Charlie Townes’s group was so active in working on the ammonia laser. I went to Stanford from ‘52 to ‘56, and then Michigan from ‘56 until ‘73. I became quite excited about the possibility of lasers in the late 1950s, and the reason was because I was aware in the mid-fifties that people were thinking about lasers, that is, extending Townes’s microwave accomplishment into the visible. I was never very excited about it because all I saw at best was the potential for a monochromatic light source, which was very interesting for spectroscopy hut I didn’t see it as a fantastic kind of thing. I first really got excited about it when I learned, I think from Gordon Gould, I forget the date of this, — is this a technical review, a real technical question, should we talk about things as they come up?
This is one of these very serious interviews which is to create a resource for scholars. Historians of science and technology will want to look at it, probably also historians of the social institutions of science, so that we try to do both the technology and the content —
— so that if I lapse into science, no problem at all?
If I don’t understand anything, I’ll ask.
The pivotal event for me actually was when I learned of Gordon Gould’s, the notion I attributed to Gordon Gould, of using a Fabry-Perot resonator. Up until then I was thinking along the lines of my prior training at Columbia, which would suggest just building a microwave cavity with a hole in it, and trying to get it to resonate on optical frequencies. But when Gordon at some conference told one that he was going to use a Fabry-Perot, it was like a blinding light globe. I realized, my God, you could get parallel light as well as monochromatic light, and the full significance of it then occurred to me. And so I was excited about it, and indeed in the late fifties I lectured on the subject. They didn’t have lasers then but I could still give lectures about them, and I was one of a cadre of young atomic physicists, spectroscopist-types in the fifties, the late fifties, because of the work I was doing at Michigan, who were really very excited and interested in the potential of having a laser.
Did the Schawlow-Townes paper make any impact that you can recall?
Not on me. I was aware of the contents of it. I was very active in research at Michigan, getting up a lab in atomic physics. I was doing a lot of optical pumping, which of course is very much a part of the art. And I just don’t recall, I don’t mean to designate the paper. The thing that made the impact on me was all of a sudden realizing in a bull session with Gordon Gould that, hey, you could use a Fabry-Perot, and then something really clicked.
That must have been quite early, because between November  when Gould first wrote down the idea of the Fabry-Perot in his notes, then the Townes article must have been available around January, ‘59, it would have made an impression on you if you hadn’t heard Gould, I would guess.
It turned out, of course, that that was very pivotal. The question of the timing of that was very pivotal in the subsequent patent litigation, the patent interferences which on that point were lost by Gould. I’m just telling you my personal exposure to it. I did learn from Gordon rather than Charlie. I know all those men extremely well. It was from Gordon that I heard about the Fabry-Perot idea. And that’s what changed me from being bemused by the possibilities of lasers, to be aroused by the possibility. It was learning of that. It was sort of like, pow, you know. I must say I learned a great deal from Charlie Townes, lots in that area of physics and certainly from Willis Lamb, and I’ve never heard of Helmer. Who’s Helmer?
Well, he was a graduate student Lamb was working with at Stanford on the ammonia beam maser. So I just thought that you might have had some conversation about that.
— of course Willis left Columbia around 1950, didn’t he?
He left Columbia in ‘52.
And I left Columbia in ‘52. Willis had quite a few students and I was busy and —
— it was about the same time that you went to Stanford.
I mean, there are a lot of people, Wieder, Maiman, post-docs —
Helmer wasn’t Lamb’s student, he was — I think he was a student in the Ginzton lab. I think he was one of Ginzton’s.
That makes a lot more sense, because Ed Ginzton would have been very much up to his ears in the possibilities of ammonia masers, things like that, because he was an electrical engineer, so that —
And others at Stanford — my God, the physics I learned off of Felix Bloch, you wouldn’t believe. But it wasn’t particularly pertinent to lasers and masers.
Now, there’s a question that belongs in between 1 and 2, about what happened after Ted Maiman came out with his discovery and so on. So why don’t we put that in?
Do you want do that now?
Yes, because it really belongs there chronologically.
You know, the way you’ve made out these questions, we’re going to be going quite a while, because you’re stimulating my memory, as I thought you probably would. That’s why I didn’t look over any of my notes. Would you like me to talk about the infamous Maiman publication? And the Maiman event?
I’d like you to talk about everything you have firsthand knowledge of.
All right. I co-chaired the First International Conference on Optical Pumping in the early summer of 1959, as the laser thing began to get feverish, and then, I’m not sure of my dates here, but I was at a Gordon Conference, I believe, in the late summer of ‘59.
You weren’t at the Schawanga Lodge Conference?
No, I missed the Schawanga Lodge Conference, as I was getting ready to go on sabbatical at Oxford. The Schawanga Lodge Conference I think was in the late fall.
Early in September I went on leave to Oxford. Now, refresh my memory on dates. Maiman was actually spring of 1960?
That’s right. May was the discovery and July was the announcement.
Now, I’m not sure of the conference, we can track this back, but I thought it was a conference in Ann Arbor though it might have been in Rochester. I believe it was in the spring.
There was a June ‘60 coherence conference in Rochester.
That’s it. That’s it. I believe that’s the one we’re talking about. Was that the conference at which Jaynes and I had the bet?
That was already around ‘66.
OK. How time flies when you’re having fun! There was a conference, and, I forget what but it was in that spring, at which I believe Oliver Heavens — wasn’t he a research associate at Columbia then?
Yes, I think he gave Townes’s work, Townes wasn’t there…
— right, he gave a paper.
Fano spoke, and Wolf had organized the conference.
Yes, OK, Emil Wolf, right. Now, at that conference, I’m only 80 percent sure it was at that conference, I’ll tell you when I’m really sure, Heavens was being funny, but many people in the room did not know it, and he implied that they had a cesium laser just about ready to go, all they had to do was plug it in, they had the end plates, they had the whole thing — you know, he was being almost conspiratorial, “just sorry I can’t give you the data, this conference is one day too soon.” Now, in the audience was Malcolm Stitch. Does that name ring a bell, Mal Stitch, who was at that time working at Hughes. Mal heard this, and already at that time Ted Maiman had had his initial results, so Mal went back — I’ll tell you, identify, exactly what’s first hand and what’s second hand. I’m giving you first hand and second hand together, because I wasn’t there when Mal went back but I know Mal Stitch very well. He and I were fellow graduate students. And as nearly as I can tell from my discussions with Ted Maiman later, Mal said “You’ve really got to get this thing published,” because Maiman already had it, “Heavens was about to get it at Columbia.” And that’s what stimulated Ted Maiman to get off the dime and really do it. Ted Maiman is and was a super good scientist, careful, studied, good scientist. I first got to know him in 1952 because he was one of Willis’s students. Ted was very good. Ted was now hung up on Stitch’s report of Heavens, was it Oliver Heavens?
I think so?
Heavens’s paper. This is all hearsay. Now I’ll get to the real stuff. Now, he then prepared his letter to the PHYS REV LETTERS announcing his result. He sent me a preprint. It is a fantastic letter. Very understated. He calls it an optical maser, it’s as if a maser was made to run in the optical. No flamboyant phrase, just straightforward science. He left out some details because the instructions in the PHYS REV LETTERS, being run then by Sam Goudsmit, a lovable, often but not always benevolent despot king — and Sam had edicted Letters will not be longer than 600 words! Kabung! So, young Ted Maiman didn’t want to have his Letter rejected, and kept it to 583 words or something. It was an understated but absolutely accurate article, that I submit no one in the field could ever have looked at without saying, “Holy shit! the guy’s got a laser!” I mean, there were still some questions, you wanted to call up and say, “Hey, did you really try this or that?” But knowing Ted Maiman to be a good scientist, knowing, Hughes Malibu to be a good lab — It was a blockbuster! Ted called me up in some anguish and said, “They rejected the letter.” At PHYS REV LETTERS. I called Sam Goudsmit. He was on vacation and I spoke with George, whoever was the next man now deceased also, not George Trigg who later took over but George at the PHYS REV LETTERS, the assistant editor, and I said, “George, what are you doing?” Because Maiman sent me the letter rejecting it, and the grounds were –- well, it was complex. It was first rejected on the grounds that it was just another maser paper, and Sam had edicted against maser papers at this point. Ted replied, “It’s not a maser, it’s a God damned laser,” but he didn’t use the word “laser.” However, now Mal Stitch and the corporate people at Hughes were saying (please forgive the vividness of my language), “God damn it, Maiman, will you publish this!” So to cover his ass academically Maiman then prepared a Letter for NATURE, and he had a press conference, or at least it was released to the press, and he wrote to Goudsmit saying, “Please, my God! Do something!” Goudsmit wrote back, I think it was in writing, which Maiman would have — have you interviewed Maiman yet?
No, not yet.
He’s on the list. Goudsmit said, “Now that you’ve published this in the papers, no way will I accept it for publication.” That’s when I called. I was sort of a young senior person in atomic physics, called Sam who used to be at Michigan — I said, “Sam, what the hell are you doing!” Sam wasn’t there but George was apologetic and said, “Really, I’ll take it up with Sam when I see him.” I said, “Look, here you’ve got a young scientist who’s trying to do everything the right way and getting screwed. Now, for heaven’s sake why not simply publish the Letter promptly, with a note of apology that the original rejection was inadvertent? Sam’s a big man, you’re a big man — you made a mistake.” And nothing happened. George called me back or I called him back a week later. He just simply reported that Goudsmit would not change his mind. And that’s why it was never in PHYS REV LETTERS. Now, there is a woman you may wish to interview. Does the name Victoria Potter ring a bell?
OK. Vicky Potter had been an undergraduate at Michigan and was then one of the assistant editors of PHYS REV LETTERS, and she knows more about this story!
Good. I haven’t been able to get much on this. (crosstalk) I haven’t been able to get the documentation from the journal.
BECAUSE IT’S GONE! That God damned Letter was sent out for review. I don’t know who it was sent out to. I will not speculate. But whoever it was sent out to was not a nice person. Whoever it was sent out to. Because if that person were at all adroit in the technology of the time, he could never have recommended not to publish it. I don’t know for a fact that it was sent out. You’d have to ask Victoria Potter. I believe it was sent out to a referee, and someone did a number, and Sam Goudsmit wasn’t a big enough man, I loved him dearly but he wasn’t a big enough man to say, “Hey, I have my head up my ass on this thing.” So that’s why Maiman’s publication — you know, of course, PHYS REV LETTERS a month later was dripping with publications from other laboratories about this or that, and Maiman’s publication was never honored as it should have been by the premier American Journal. Just sort of a sad historical or hysterical note. The essence of what I’ve told you is, I believe, absolutely true. The details are some hearsay, some not — I definitely know about my conversation with George what’s his name, and I can retrieve that from my memory bank, and I certainly know of my conversation with Ted Maiman. It’s amusing, because it’s straightened out now. Justice is done. It’s just, it would have been much more glorious if the PHYSICAL REVIEW could have been the correct appropriate publication. Ted Maiman has been appropriately honored for a very important and exciting contribution, but at the time there was a lot of ill feeling. The Bell Labs Mafia were at high tide in every respect, and it’s just unfortunate all around.
Good. I’ll try to get to Potter, because as I say I haven’t been able to get any documents yet on this.
I think she’ll tell you that much of what I’ve said, but she doesn’t remember, — she went back in the files not too long ago and tried to recover it. I don’t think there’s anything illegal, I think they just kept the files just so long and then stopped.
All right, now, I threw in with the question about the background at Ann Arbor in terms of relations with the electronics industry. I want to know something about how you came to be associated with Trion.
OK. I became associated with Trion right after the laser was born. One of our graduate students research associates out at what was then called Willow Run, a young fellow called Lloyd Cross, and Lloyd went to start a company to make lasers, ruby lasers. This was within months after Maiman, because he made one work. And I agreed to work with him on it, I was a pretty young professor then, as a consultant, and instead of a fee I said I’ll take some stock. It was a minor amount, I was not a major stockholder, but I exchanged it for consulting. Then Lloyd and a man named Doug (Douglas) Linn started Trion Instruments, which proved for a while to be wildly successful, but they under-priced their laser. They were afraid of charging too much, so they had a laser TR-1, one of which I rented to do our optical harmonic experiments, because I couldn’t afford to buy it on my research contract. I checked it quite carefully with the university lawyer against conflict of interest because I then had also an equity interest in the company, and the answer was no, because it was clearly sole source, it was the only company that made one. But when other companies came in, Lloyd, was it Lloyd or I, realized we’d made a mistake, pricing it at $5000. It should have been priced at 25,000 because the nearest competitor was one-tenth the energy and it was five times the price or something. I think Hughes actually tried to make one, I forget the name of the company —
Hughes certainly did try to and a number of other companies. I haven’t spoken to Lloyd Cross, I have spoken to Lee Cross of course a little bit.
Lloyd was really an undisciplined genius. Lloyd has dropped out of society. I don’t know where he is right now, I can tell you all about him later, but — very interesting.
I tried to get hold of him in San Francisco but I wasn’t able to.
I’ve lost track or him too. The last time I saw Lloyd, the time before last which was some years ago, he and his mistress were my house guests here, and she, Pam, was a fantastic model. Lloyd was then doing these holograms, of which one is now at the Planetarium. You may have seen that, with the girl winking as you walk around it?
No. I haven’t seen that one.
And it’s super, and Pam is the only woman in the world who could have done these things, because it took 45 seconds to take the 360 pictures. So it’s not easy to do one wink for 45 seconds! Pam had the remarkable ability to do this. She could do just a lovely blowing of a kiss gesture or a wink in super-slow motion, which was what was necessary. She was the only one I saw ever – the others were all kind of jerky. But Pam had an enormous skill — Lloyd and Pam stayed with us. I saw him one subsequent time and then he disappeared. Remarkable young man. Radiation weapons systems?
OK, yes. This is one of Seidel’s questions.
That is something Seidel and I should take up. I’m sure Trion did some study, but I would say in the early sixties, we were looking at radiation weapons quite seriously and in a classified context. I wouldn’t have thought, from my memory at the time, they were one of the principal players. They made contributions because they had the industrial expertise, but it was not on a par with Hughes and some other companies, in terms of just the heavy duty military industrial muscle for that kind of stuff. That whole classified area is extremely interesting, much of which is unclassified now, and much of which I can talk about in an unclassified way, but probably Seidel would be the person to do it with, so we don’t have to stop and think each time, is that classified or not? He has a clearance?
Good. He has a clearance, and he also has a kind of familiarity with this whole area which I think is going to make that conversation more helpful anyway, fruitful.
There is a lot of very interesting stuff I might just mention in passing, things that have been left out by the media. Star Wars ain’t new. What’s new is all of a sudden the President saying, “Why don’t the scientists get off their ass and do something about it?” But we’ve been working on that problem since 1955.
That I didn’t know.
The first paper studies on that were done in 1958, and by 1960 we had a full-blown program called Project Defender, at the Advanced Research Project Agency, the program ran some years later, dedicated to research and technology in anti-missile defense. That’s over 26 years ago that that was unfolding. That doesn’t prove anything. It’s just that we know a lot about it and how hard it is. Anyway we’ll never finish this interview if I keep free associating that way.
Well, now, the Jarrel-Ash-Trion work, is that an interesting topic?
It is. It is just a little bit muddy. I think I invented that spectrometer, but there was some patent interference on that that muddies that water. There is something interesting there, not so much the spectrometer as there is, what led up to it. I was very interested, and in fact I gave the first paper in the United States on the possibility of using lasers for thermonuclear fusion, a paper attended by Nikolai Basov of the Soviet Union in Washington circa spring of ‘61, the national meeting of the optical society, on application of high powered lasers, and I talked about nonlinear optics and lots of things, but I also spent a few minutes about fusion. My thesis was that you couldn’t do it — economically — but at least it was in principle possible if you could get to very high temperatures and densities. However, in fact, I started a program in fusion at Ann Arbor in 1961, and what had stimulated it was, Bell Labs had announced in its papers that by blasting a laser at a steel razor blade or a carbon block, they had observed very high spectral temperatures by doing spectroscopy on the lines of carbon or iron or whatever was used. It was suggestive of 20,000 degrees. I remember that figure. Whether that was published or whether it was given in a paper, I don’t know, but that was just a 1 joule laser, and 20,000 degrees with that and if you would scale it up — it’s possible, let’s think of fusion. I was the first person to discuss it in the States, and Nikolai Basov is a good friend of mine. We discussed it in the Soviet Union as recently as two years ago. He had been very stimulated by that paper, though he said he was already thinking the same thing himself and I’m sure that was true. You didn’t have to be a genius to think of it. But anyway, in Ann Arbor again in that spring, after doing my nonlinear optics stuff, I did some spectroscopy, and indeed there were all these lines, the classic thing, you get a jet of light — I got suspicious. So I did the same experiment the Bell Labs people did and got the same results. Then I did it in an inert atmosphere, argon and helium and nitrogen, and it all disappeared. It disappeared. The spectra disappeared. And then I learned something that was just obvious. What Bell Labs was doing was, they were burning carbon in air. Burn carbon in air, you get these high spectral temperatures. The actual temperature of the jet was a couple of thousand Kelvin
With this fusion work at Ann Arbor in the spring of ‘61, did you get at all involved with the AEC fusion people at that time?
Oh, you bet. Would you like me to —?
Let’s see, that was Ruark at that time.
I can tell you an anecdote, that’s not too important. I — let me finish off this first thing. I then learned that Bell Labs had just made a mistake, the Bell Labs people — they reported these high temperatures, but the high temperatures were due to burning. So they revised it downward, and that was before I gave my Washington paper. That’s why I said in the paper, the chances of direct laser excitation with the lasers we have now are on the low side at best, and that was true with the lasers we had. We didn’t have Q switching. We hadn’t announced yet a super high power laser. But I still went ahead it. I said, well, you know, if that’s the case, let’s use it as a teaspoon, since it’s throwing up material which we know was burning. I said, why don’t we throw up the material between two electrodes, let there be a discharge, and get the excitation that way? That was the birth of the Jarrell-Ash-Trion laser spectrometer. The patent interference came about because the chap at Jarrel-Ash felt that he had made that suggestion. In fact he hadn’t. But in fact it’s kind of irrelevant. The instrument was made for a while. It has limited utility. It’s an interesting historical footnote. But again, I don’t mean to sound antipathetic to Bell Labs. I had a great deal of respect for them. But in the early sixties, there were a number of folks there who were just sloppy in their reporting, eager to get into press before they did their homework, and it raised a lot of problems. Anyway, that was the birth of that.
I want to digress on this fusion business for a minute. You said that you did get involved with the —
OK, after my paper in Washington. At that meeting I announced that we were starting research at Ann Arbor, with the little glass spheres and so on. I got a telegram from the AEC saying, “All your work in fusion is now classified Secret Restricted.” which was a very powerful classification, Secret Restricted at that time – they had lots of different clearances — but that classification meant you had to have an armed guard in front of your door, and nobody but cleared personnel could go in the building, and all sorts of crap. So I called Charlie Marshall, who was the then director of security for the AEC. I said in my delicate way, “What the hell are you doing?” He said, “I was just trying to get your attention.” So I flew down to Washington and had a meeting with Charlie Marshall and I think George Ragosa, I’m not sure of that, at the AEC — a senior technical man. We sat in the room and they explained to me an interesting part of the Security Act, as far as it goes to the AEC, and that was the AEC was never allowed to raise the classification of a project, they could only lower it, so they said, “Look, I don’t know what you’ve got out there, but if you’ve got a trigger for a potential thermonuclear weapon, and I allow you to work on it unclassified, then I can never classify it.” So he said, “What I’d like to do is to get about 30 or 40 scientists together, and really study this problem next summer, to find out where — I mean, obviously,” he said, “at some level, the work can be unclassified. If you’re working on a 10 joule laser I’m not going to classify that.” I said, “Hey, why don’t you let three or four smart guys sit down in your office and see whether they can draft something that’s acceptable. Don’t go to a congress of 40 scientists.” They said, “OK.” One of the men was Fritz Byrne, Office of Naval Research. The second man was a char from Princeton whose name I forget, damn it, but he was head of Princeton Plasma Fusion Work at that stage.
No, not Spitzer. I just can’t get it. It was a chap from Princeton. There was an interesting situation there. There was a senior AEC man who was really kind of formal. And I remember he’d driven out to Germantown in a government limousine. There was a very funny incident at that meeting. I think it was at that meeting, or the one before or after — I’m just digressing — I was then — I’ll reserve the anecdote for later, it’s a distraction, but it was an amusing thing. We three chaps sat down. We had travel orders to be closeted for three days. After two hours we were done, because we calculated, and it turns out correctly, the power level that would be required under the most optimistic conditions to get a trigger for thermonuclear fusion, and it was 12 orders of magnitude beyond anything we were thinking of then. A huge amount. Not beyond what’s available now. Right now we’re into 1015 plus watts. The most we could think of was a megawatt or 10 megawatts. It was just way off. We knew it was going to be power densities like 1015 watts plus, as indeed is the case. Our calculation was not too bad. You can’t miss on our calculation too much by just. And Charlie Marshall agreed. And he asked us, “Do you all three agree?” We said, “Yes. So that led to lifting the classification, and in fact we published a level and said anything about 1015 watts or what, I forget, it was a combination of energy and power, would he classified. Anything below that was not. That automatically let us do anything that would be possible circa 1960. And Charlie Marshall was very reasonable about that. They never had the big congress. That was it. We got a telegram the next day saying they withdrew the restrictions. And off we went. I was kind of pleased with my call on that one.
That’s an interesting story, and so is the connection of the spectrometer with the fusion. I wanted to ask about the optical harmonics experiment. You have a very soft voice and I [should move the microphone] — (Franken testing ...)
Where do we go now?
We’re going to go to question 4 and talk about —
That’s going to be a long answer, but let me give it to you.
That’s what I want, most interesting.
Now I come to the optical harmonics experiment and other effects — and excellent — OK — I’ll refresh my memory. I think we published optical harmonics in ‘61. So it was in the spring of 1961 — I may be off a year on this —
— no, that’s right. Somebody told me you started it after the OSA —
That’s right. Let me tell you about the OSA meeting. It was held in Pittsburgh. One of the reasons, the primary reason the Optical Society of America got off its classic lens design duff and got into the modern age was a woman named Mary Warga, who I believe is still alive, although in bad shape. Mary was executive secretary of the Optical Society, and she grabbed that Society kicking and screaming in the 20th century and said, “We’re going to have a laser meeting,” and that was one of the first major professional meetings. It was in the spring of 1961 in Pittsburgh. That was Panic City. The halls were packed. Normally if you had an invited paper at the Optical Society, you might draw a hundred people. There might be two or three clickety click cameras taking pictures of the slides. These halls were packed, the ballroom was packed, for these papers. I remember as a high point Art Schawlow getting up to give a talk. Every slide he projected, there was a veritable staccato machine gun fire of Minoltas going off. It was unbelievable! Panicsville. Everybody wanted to get in on it.
But the high point for me was, Art went to the blackboard, wouldn’t use a View graph, and he said, “Now, we think at the Labs that there are three mechanisms that could explain this spiking phenomenon in ruby,” and he was facing, the blackboard when he said it. He wrote down the number 1 for the first one, turned away, and I heard half a dozen cameras go off! I mean, that was amazing. As I sat listening to it, I kept hearing, “Lasers are fantastic — eye surgery, communication, eye surgery, communication” — eye surgery and communication were all anyone could think about. And I was thinking of a story. Now, this is first hand. I had just heard a very famous, now a very famous slightly off color story that I had heard for the first time just the day before I’d come down to the conference, and the story has to do with two boys whose father calls in a psychiatrist on an emergency call. The psychiatrist comes in, “What’s the problem?” He says, “Well, Doctor, really, one of my kids is an optimist and one is a pessimist, and it seems very intense and I’m concerned.” The psychiatrist says, “You called me on a house call for that? Well, while I’m here I’ll look at them.” So he goes up stairs, and there is Davy in the nursery, and Davy is surrounded by all the toys and treasures that a little boy could ever want, all the fish tanks and tropical fish and iguanas and airplanes and radio components and the whole thing, and he’s sitting in the midst of all these treasures bawling his eyes out. The psychiatrist says, “What’s the problem?” The kid looks up, tears streaming down his cheeks, “Gee, Mister, with all this perfection, nothing can get any better, it’s so depressing I can’t stand it.” That’s pretty serious. So he goes around to look at the other boy, Jimmy. Now, Jimmy is in the courtyard, and Jimmy is in absolute glee because he has just discovered some droppings of the horse. So he runs over and picks these things up and throws them in the air and says “Whee!” He looks around and sees another pile and he gets even more excited. That’s one manic kid. The psychiatrist goes over to Jimmy as he’s stooping, by the third pile of horse manure, and he says, “Hey, Jimmy, what are you so excited about?” He looks up and says, “Gee, Mister, with all this horse shit around, there’s bound to be a horse!” Now, that just kept going through my mind as I listened to the Bell Labs folk going on about communications and eye surgery and communications, and that’s all they were saying.
Put the panic — So I began to think, I forget whose paper it was, my mind began wandering, there’s got to be something unique here, and I calculated the strength of the electric field in an optical laser beam, taking the largest estimates of just an ordinary beam the order of a joule in milliseconds, so you’d have a few kilowatt laser, focus it down to a 10 micron spot, and all of a sudden up into quite a strong intensity, megawatts per square centimeter. I did some calculations and I discovered, holy cow, there are going to be electric fields like 100,000 volts per centimeter! And I realized then that you could do something with it, that you were driving atoms so hard, because after all atomic electric fields are on the order of 109 volts per centimeter — this was getting to within 10-4, 10-3 of an atomic electric field. That’s got to be able to do something important for atoms, because I already knew that fields much less than that could auto-ionize atoms, called the Auger effect. So I did a rough estimate, using very simple perturbation theory, and dimensional arguments, and I remember sitting down and figuring it out from scratch, the expression sin2ωτ = ½ (1-cos2ωτ) and I realized, my God, you’ve got a second harmonic. That’s the effect of the nonlinear term. And I did a crude estimate, if you took a laser and you focused it into any material, and I was thinking then I’d use quartz, and I knew what the atomic energy levels were and I could make the calculations that there should be enough radiation produced to be detectable at the second harmonic. I got so excited about that, I left the conference and went home. I actually quit – I said to myself “now, wait a second, there is something you can do!”
Now, at this point were you already renting a Trion?
No. No, no, this was spring of ‘61. I got excited enough that I went home. I got home that night and I called my very good friend Gaby Weinreich, who is a solid state experimentalist and theorist, a super physicist, and I said, “Hey, what’s wrong with this idea?” And I described it to him. I think I may have described it to him in his office the next day — he said, “I don’t see anything, wrong with that.” So I went to see Wilbur Peters, who was a senior experimentalist then, and I said, “Hey, would you collaborate with Gaby and me? Try this out? I’m going to go rent —” I’d already called Lloyd and said, “Hey, I’ve got this hot idea, can I rent a laser?” So we were all pretty excited about it. I made all the calculations a half a dozen times, just sort of dimensional arguments that I could reproduce — straightforward basic physics. And so we decided we would take fused quartz and hit it with a laser, here was your spectrograph and the whole experiment that we actually did, the detector photograph, and that night, Gaby called and said, “We’ve got a problem. It won’t work on fused quartz. It has to be crystalline quartz.” I said, “I don’t understand,” and he explained, — I will state unequivocally, a I did then, I do not think I would have picked that up myself. Because I wasn’t a solid state physicist, I was an atomic physicist. I understood the argument immediately after Gaby gave it to me, that we had to go to a crystal which lacked a center of inversion, we couldn’t use an isotropic substance like fused quartz. Gaby has said over the years, “Aw, Franken, if I wasn’t around you would have figured it out after a while.” I personally think if Gaby hadn’t been around I would have tried the experiment, which was a very difficult one at best, and probably abandoned it. Maybe not. I don’t know. But Gaby was absolutely essential. Without Gaby Weinreich, I don’t think the Ann Arbor work would have happened. Without Peter Franken it would never have started, without Gaby it couldn’t have succeeded. Wilbur Peters’ great expertise in experimental spectroscopy was crucial. This is the only experiment I know of where all four authors were crucial. Can I tell you about Alan Hill? Gaby’s role was to recognize that symmetry problem, so we switched, instead of fused quartz we used crystalline, which we had lying around too, but I wouldn’t have thought of it. It was not obvious at the time. It wasn’t obvious to Gaby either because it was 20 hours before he called me up at 10 o’clock at night and said, “We’ve got a problem, don’t use fused quartz, it lacks a center of inversion.” Very important insight. Now, Alan Hill, have you heard about Alan Hill? He’s still alive and well in Albuquerque, and someone you may want to interview for this, he was very pivotal to laser history. OK, I met Alan Hill around 1959, a gawky young sophomore at the University of Michigan who was in one of my recitation or discussion sections in freshman physics. I don’t know how come but I didn’t have to teach the main lectures, I was able to just loaf along teaching sections. And we’d been doing magnetism, and this gawky kid, whom I recognized from the class, but was never very impressive as a student, came up and said, “Gee, Professor Franken, I was thinking, last night we were talking about magnetic force effects and so on, if I took an aluminum tube and I wrapped a big copper loop around it and I sent a big current through that copper loop, that should crush the aluminum tube through magnetic force.” I said, “Yes, I think it would crush it.” He said, “Now, if I took the same aluminum tube and I ran a big current through it, it should stretch it, shouldn’t it?” I said, “No, I think you’re wrong, it would compress it.” He said, “I think I’m right. I tried it last night.” And he reached into his briefcase and he pulled out the first tube, which he had wrapped the thing around — he had a 20,000 microfarad capacitor bank in his garage, of all surplus capacitors! And it looked like a God damn giant had just crushed it. Then he said, “But let me show you the other experiment,” and took another tube out of his briefcase. I was just dumbfounded. Here’s this kid, he hears a lecture, he goes home and he tries an experiment that we couldn’t have done at the University of Michigan. And he wasn’t trying to trap me. I mean, he just wanted to understand it, because he wanted to understand how these rules I was teaching could reconcile with his experiments. Well, I said, “You sure a hell have the best of me.” Well, that was my introduction to Alan Hill. He was a sophomore. That impressed me. I mean, that just impressed me. So that summer now of ‘61, he is still an undergraduate, a junior or senior but still an undergraduate. I had enough money to rent the laser and I had enough money to pay a student, and I realized, I was busy with a lot of stuff, running a big atomic physics program, and Gaby wasn’t going to get in the lab, and Pete was very hard to get to apply. We needed some guy to go in and make things work. So I asked Alan if he would work on it, and he said, “Sure.” So Alan that summer and I were the principal ones who worked on it. But without Alan here — Alan is a genius with machines.
Was he still an undergraduate? About a senior?
Oh yes. He was a senior. And I learned a lot of things that summer, including that if you use liquid nitrogen for the laser — the experiments were on the fourth floor, the elevator was being repaired, and lugging up 50 litre tanks of liquid hydrogen was not — Alan and I got very strong. But Alan set up the capacitor banks, and really tweaked that laser going. He was the one in fact who ran the first plate on which we actually got a sign. Once again, I think without Alan’s just great experimental capabilities, it wouldn’t have gone. It might have but I don’t think so. So that was Alan Hill’s role. In fact, when we published the Letter — I didn’t want to screw around with Goudsmit any longer, because I was still burned about Maiman — we put an asterisk, you know the way papers are usually published? And after Alan Hill’s name, we were going to put an asterisk, “* Submitted in partial fulfillment for the Bachelor of Arts degree at the University of Michigan.” And I really wanted to do it, but I decided not to. So that’s a long winded thing — again, four men were involved in that. I will take full credit for having stimulated it, started it, conceived of it. I do not think it would have worked without Gaby Weinreich, because I think I would have gone down the wrong path. Without Wilbur Peters, I wouldn’t have had a spectrometer and the background knowledge to work with it. Without Alan Hill to actually tweak the screws, we probably wouldn’t have got it going. It was a very tough experiment. Not easy.
What were the hard parts?
The hard parts were, we didn’t have phase matching. We understood, and Gaby and I independently understood that, that you had to have phase matching. Without phase matching and without sensitive detectors, using photographic plates, you had to have an alignment, that spot of light on the surface of the crystal, within half a ten thousandth of an inch. And it was an F 22 spectrometer. That thing had to be really lined up. Very hard to do the alignment. And every time we pulsed that laser, the laser would jump. It was like an electric shock, whoo, with the cables. So it was lining up, fire, relining, fire, relining, fire, and it went on for months. Bromberg Wasn’t there a way to keep the laser from jumping?
Not to that precision. We clamped it down, but you could actually see the table, it was a wooden table, go oomph! And it was hot, and the air conditioning wasn’t working, and we were lugging liquid nitrogen — It was not easy. And that first plate was just barely there. Now, I notice you ask about the infamous spot.
Well, when I looked at it of course it wasn’t there.
That’s right. Would you like to know why it’s not there?
I understood somebody airbrushed it out.
Do you know why?
I’m told they thought it was an error.
Well, what happened is, as you may know, to this day, but certainly then, when you submit a paper, you submit the figures, and you write on the back of the figures, figure 3 or whatever, and the figure captions are separate. And I never thought of why that was. I mean, I always thought you stuck figure captions on the figures, but the instructions were, they had to be separate. The reason for that was, in PHYSICAL PEVIEW LETTEPS, the Letters were edited in Brookhaven but the printing and everything was done in Lancaster, Pennsylvania. It may still be done there for all I know. Now, that’s why they separate the figure captions from the figures, because the figure captions stay with a Xerox or some copy of the figures in Brookhaven, but the original photographs, and figures then had to be on glossy photographs, are sent to Lancaster, where the lithographers prepare the plates. Now, the basic toilet training of a lithographer is, he doesn’t like spots. So he saw the arrow and the blotch but the little spot under the arrow, he figured — since he didn’t have the figure caption, the figure caption says the arrow points to the first plate in which unambiguous evidence of, etc. — so he erased it. I have the original. It was there. It was interesting, because I had a debate with my colleagues, should we send in that original plate or should we send in the blown up photomicrograph of the spot which shows all the grain? I said “Let’s for historical reasons — just do the first plate.” And for historical reasons some sonuvabitch in Lancaster erased it, because he figured it was a defect! So that’s how that occurred. I also prepared a quick draft of the Letter to send in to the PHYSICAL REVIEW LETTERS right afterwards just showing the plate with an arrow pointing to 2200 angstroms as evidence of the first unambiguous failure to observe third harmonics! Again I tended to be a bit of a jokester and my colleagues said, “Hey, let’s not screw around, we’ve got something important here, don’t screw it up.”
You must have had quite bewildered responses to that. I wanted to ask if you had things in your files from that period which document the experimentation. I think that’s a part of the record that —
I did get some stuff, like the original plates, some of them to Sivowitch [at the Smithsonian Institution].
That’s a hard name.
So he has some of those materials.
The documentation is there and I should really look through it. I’ve got a correspondence file on optical harmonics relating to that Letter. You could just look through and see if there’s anything there. I just haven’t done it in 25 years.
I’d love to because it would be interesting to see people’s immediate responses at the time.
Well, one of them is a framed check from Willis Lamb. Did Willis tell you about the check?
Now, this isn’t the Jaynes thing?
No, that’s $50.
This one — the sacred bet in physics in that time frame was a nickel. The vulgar bet is five dollars, “I’ll bet you five bucks,” but if it’s really important, “I’ll bet you a nickel.” And I learned that from Felix Bloch. Matters of important principle, you bet a nickel on. The reason I went to Oxford in ‘59 for my sabbatical was to spend it with Willis. He’s been my teacher, a man for whom I then and now obviously have a reverence and affection for that won’t stop. Willis was then, as now, an acerbic son of a gun, and he and Ursula came to visit us in Ann Arbor that summer, while I was just starting out the experiment, and he picked on me unmercifully as to why this couldn’t possibly work. A lot of people did, because at that time, we were all thinking photons, and you can’t change the frequency of a photon. That was what was so revolutionary about the thought that you could have optical harmonics. Today we know better. We think of the electromagnetic field as classical and you can double the frequency in a classical field easily because of nonlinearity but in the 1959, ‘60 period, it was a revolutionary thought. This is why we were never scooped. Bell Labs people came through, saw what we were doing, and laughed. We didn’t keep our work secret. We worked on it four or five months. “Harmonics, what are you talking about? You can’t do that.”
You can get harmonics in low frequencies, and these are the same kinds of radiation.
Oh, you get harmonics in sound, but not in electromagnetic —
— don’t you get microwave harmonics —
Oh yes, you can do that. But you see, we were thinking, then — that is, we tended to think very much that — and I broke away from this in my studies in Oxford, 1959, level crossing spectroscopy — we tended to think of light being photons, Einstein, after all. But at lower frequencies it’s classical. I mean, we were confused then. Not just me, I mean the whole God damned field. At that stage I don’t think I was confused, curiously, because of a lot of guidance from Willis as I worked through the theory of level-crossing spectroscopy in 1959. I realized, “Hey, you can use c1ascal electromagnetic theory even in quantum mechanical phenomena. It’s the atoms that are quantized, not the field. For these events.” So that’s what led me to be unharnessed to think about the harmonic generation, but most physicists my age, or older, my generation — “You’re crazy.” He really whipped me up and down. In fact, I remember one thing he said, “Well, Peter, when I leave this weekend, you’ll be a sadder but wiser young man.” And Ursula was saying, “You haven’t seen Peter for years, stop picking on him!” God, what nonsense. So we did get it to work. So when Willis was back at Oxford, he sent me a check for three pence, which was the English equivalent of a nickel. And I still have that check and it’s in my physics department office, all framed. I never cashed it. And very seriously for years Willis said, “Please, Peter, will you cash that check, I can’t balance my accounts!” I still have the original check. And that was Willis’s way of saying, “Hey, I was wrong.”
That’s strange, because it was Lamb who was teaching you that the photon was —
— we were working it together. I think in some ways, I wasn’t aware of Jaynes’s work then, but I was really pushing more and more and was publishing some on just the matter that you could treat all interactions of radiation and matter by classical electric and magnetic E0cosωτ, of course, and forget about second quantization and all the bra and kets that Dirac had and so on, and put the quantum mechanics strictly on the atom. You could get everything except the so-called non-radiative effects like the Lamb shift and the anomalous moment of electron, and that was the bet I had with Ed Jaynes, because Ed was claiming to do everything and I claimed, “No, I think it will do everything, like photoelectric effect and harmonic generation and so on, but you can’t do Lamb shift or the anomalous moment of the electron, “and that’s when you’ve got the multiple?” We made the bet at the conference. And Willis held the stakes.
So let’s put aside some of the time that you have left to look at those. Now, the next question was about the Ford group, because they came in fairly quickly and so did Bell, and I notice one of the things they did was to use isotropic materials for the biasing field.
— that was something —
— you did your first paper on.
We did predict that. I worked closely with Bob Terhune, who used to be a student of Wilbur Peters at Ann Arbor, and he was at Ford, and in fact, he lent us some ADP, ammonium dihydrogen-phosphate, a little chip off the huge crystal they had, which was on the cover of SCIENTIFIC AMERICAN, and you can clearly see a little spot missing from the corner of this big crystal of ADP, and that’s the little soot that Bob Terhune hacked off to lend to me that summer, because after we did quartz we began to look at other materials like ADP. It was a very close association. The — I’d like to tell you an anecdote about that time. Independently Giordmaine at Bell Labs and Terhune and Maker at Ford discovered index matching. I worked on that. I recognized, Gaby and I independently recognized there was an index-matching problem. I worked on some solutions that we did publish, which were alternating left and right handed quartz, and I also speculated on doping materials which ultimately was made to work. But then George sent me a preprint of his Letter on index matching, where you use the extraordinary and ordinary. I was so enthralled by that. I mean, it was just “what a clever idea!” — to me, that kind of an idea, I’d never thought of that. I would never think of it. Jesus, that was fine! I called Joe, for whom I have tremendous respect, and said, “Joe, that’s fantastic.” He said, “Yes, isn’t it?” He was just so excited about it. And I’d never thought of that. That was so neat. And also I learned later that Terhune had done the same thing. But at that time we were publishing our paper on optical mixing or something.
I think that subject goes right in here.
Now, what Joe and I decided to do, you know, there was such jealousy, antipathy, in all the work and competitiveness among competitors, I put an acknowledgment in our paper of gratitude for discussions to Giordmaine, although he had nothing to do with our paper, and he put the same thing in, in his paper, although we had nothing to do with his, just to get back in print with a sense of gentlemanliness. “We appreciate many interesting discussions with Giordmaine,” and he hadn’t helped us one bit and we hadn’t helped him one bit, but we wanted to put that back in, “Hey, come on gang, let’s get back to having fun in physics rather than cutting each other’s throats.” I’d also like to tell you another anecdote about Gaby Weinreich, who was really a super man. About a year after this, we did three epochal things in Ann Arbor -– optical harmonic generation, optical mixing, and optical rectification. But boy, were there a lot of other people in the field, Terhune and Maker, Giordmaine and Bob Miller… and we went, Gaby and I went to a meeting of the Physical Society in New York, a big national meeting. We were sitting in the front row, at an invited paper session, four papers on nonlinear optics, none of which were being given by us. We were already eclipsed. And I was feeling bad about it. We could have done this third harmonics stuff, these are all ideas that were near at hand, we had the equipment. I mentioned it to Gaby. And Gaby said something to me that was very profound, that made me feel better forever. He said, “You don’t understand, Peter. We weren’t lazy, we were stupid. We never thought of it.” I’ve thought of that so many times. I felt so much better, because as a physicist, compulsive, burning with a hard gem-like flame, as Walter Pater put it, I could not live with myself as being a lazy bastard, but I could live with myself as being stupid! And what a blinding insight of Gaby’s –- relax and enjoy it. And I relaxed and enjoyed the session. You’re stupid, — that’s fine, but don’t call me lazy, call me stupid, that’s all right! I just hadn’t been smart enough to think of everything. I’d thought of a hell of a lot. But I didn’t think of everything. Gaby made me feel so much better, because I was really feeling, we should have been doing that stuff, because we were all competitive. But I was just stupid.
That competition was probably very hard.
It was. It was exhilarating, it was hard, but Gaby made me feel so much better with that recognition. Gaby was a super warm man who, interestingly enough, emasculated himself in the world of physics. He was so bright and capable but he wouldn’t push hard for publication of things. He got a paper rejected. It was a very good rarer he wrote in 1962. (Rejected) by the PHYSICAL REVIEW. And his idea was “Oh, fuck it.” He had a good rejoinder but he wouldn’t make it. So he resigned from the Physical Society and just never published much more. But Gaby’s presence in the 1960s and early 1970s, in Ann Arbor — it wasn’t worth a damn in publications — but his presence improved the quality of my physics and Michael Sanders’ physics and half a dozen others enormously. He was a catalyst. He was a guru. Gaby was just a very smart physicist. He still is. But I was the young aggressive tiger, and Mike Sanders and others who were there, and Gaby was the guru. At age 32 he decided to be a guru and he was. As evidenced by the recognition of the students there.
Good. Now, the next question was about Bloembergen, because there seems to be something going on. They of course started with your paper, and then there was this work on optical rectification and its relation to linear electro-optics effects, and some kind of discussion about testing out their theory and getting the coefficients. I’m very much interested in the relation of these — the relation between theoretical papers and experimental papers anyway, so I’m generally interested in what ABDP meant.
That’s Armstrong, Bloembergen, Ducuing and Pershan. Let me tell you about that paper in an uninhibited way. Gaby and I were groping with trying to develop — we knew we could do this thing quantum mechanically, we’d already done it semi-classically — the Bloembergen paper came out, and it was very difficult to read at that time, very complex, and so at that time, this was now around 1962, I invited over as a young research associate a fresh PhD I’d met at Oxford named John Ward. We decided to write a review paper that summer, a review paper that John and I wrote.
They didn’t commission that?
No. I mean, I talked to the editor about doing a review paper. He said, “Great.” And I think it’s an excellent paper. I mean, just in terms of elegance and style and clarity, I think that paper John and I did is super. Now, Bloembergen’s paper came out then, and John and I divided things up and I did the report on that, and I couldn’t understand Nico’s (Bloembergen’s) paper. I knew what he was saying, and that was revelatory. Nico led the way into the formalism. Ah, I see how they can do that. But I re-did it so I could understand it. I do think my work -– I’m now talking pedagogy, I’m not talking, inspiration — is far better. Nico’s was a rather tortuous development. What I’m saying is, I got the joke, as Uhlenbeck would call it, I saw what Nico was doing, but I couldn’t — it was going to be a review paper — but I couldn’t abstract from his paper, so I did it from scratch, taking his teaching, so my contribution there was I think the first really clear treatment quantum mechanically of the subject; but I couldn’t have done it without Bloembergen, who led the way on that. Bloembergen really saw the structure of quantum mechanics in that, and once he gave the good clues, I was able to do a good job of pedagogy. Nico wrote a lot in that period. He also did the so-called first book on nonlinear optics, which I think is a poor book because Nico gave lecture notes, and just transcribed them, but he didn’t work hard. That was only a 20 page review paper John and I did, and we worked all summer on it, because a review paper is supposed to teach, and not claim, it’s supposed to teach. So I really felt it was a deficiency in Bloembergen’s group, they were lousy teachers, but Nico’s contributions on the theoretical side of the science was outstanding and very important.
Do you have much sense of how your paper was received?
Well, by Nico, but by the group.
My impression is, it was received with enormous exuberance. It was revelatory. Nobody was thinking about that at the time. I’ve never in all these years, had somebody come up to me and say, “You son of a bitch, you scooped me, because I was about ready to do that.” Nobody was working on it. And the Bell Labs — have you picked that up? My impression is —
No, I haven’t looked for that. I certainly have not heard it, and almost every other subject in lasers, you hear that.
— the irony here, do you remember Sergio Porto? Has that name come up?
Yes, in connection with Raman effects.
Sergio Porto was a visiting physicist from Brazil at Bell Labs, and he visited us, in a different connection, on Raman spectroscopy, some months after the announcement of our work, and he was looking, around at our apparatus on harmonic generation. He said, “Yes, that was the work we started at Bell Labs.” Arrogant — he was just misinformed — but the Bell Labs Mafia was in full regalia then. And Sergio was infected with the Bell Labs arrogance. I knew Sergio over the years. I think he was a very bright man, but there was a final ironic and painful end to that story. Some years ago, four or five years ago now, Sergio and I and several others were at the X Conference in Nonlinear Optics in Siberia, Novosibirsk, and Sergio was a very macho man, in his early fifties then, and his wife was with him. She couldn’t constrain him. He went swimming that day, lots of beer, 99 degrees F., 99 percent humidity, and there was going to be an East-West soccer game, and I suited up for it, put bathing suit on and sneakers, and it was just too God damned hot. There were 11 players for the Western team. So I just watched. In fact I had a camera, I was taking pictures. And I saw a crowd developing. These men were playing hard, particularly Sergio and Ezekial from MIT. Really a tough department. I don’t know, I can’t even play, but my God — Sergio dropped dead from a coronary. I went over when I saw what was going on, gave him CPR, worked on his dying body for 45 minutes in a field in the middle of Siberia until the Russians could finally get their act together. By then it was too late. I worked very hard with the Russians, and with the autopsy and all the logistics of getting his body back to Brazil. I was with him at the end of his life, and was kind of with him at the beginning of his professional lab, which was characterized by his claiming “All this work we’ve done at Bell Labs.” Not “we” personally, but “we” Bell Labs. His sons are doing fine and so is his wife.
OK, you want to go to the next page [of questions]?
Sure. I presume what you’re finding is, there’s always more that comes out than was originally in the question.
Yes, sure. Who knows whether these questions are on the mark.
They’re good questions.
I drew them up in a great hurry, I must say. Well, the other things I know about, coming out, are your optical mixing and optical rectification — some things we ought to talk about —
They were difficult. All the experiments were very difficult. I mean, they’re easy to do today, a quarter of a century later, you just take things off the shelf and do them, but at that time the mixing was terribly tough, because now we had to get two lasers. By the way, I was going to do mixing with a neodymium-YAG laser, and Wilbur Peters came up with a really neat idea that we could use two ruby lasers, one at room temperature, one at liquid nitrogen temperature, separated by 6 angstroms.
Now, what was the reason for using two lasers?
Easier. I mean, we all knew that there was a difference in wavelength, but it was Pete who made that suggestion. Wilbur used to play bridge at lunch very often, and I had already persuaded Lloyd Cross to build the neodymium laser, and Pete said, “Why not take the two ruby lasers and just let one go at room temperature?” Bingo. You know, that’s the way research very often goes. It was a neat thought. So we did that. We just rented a second Trion laser, ran it at room temperature, but still, we could have done it the way we proposed — in fact, as it was done later — but it made it easier. Even so it was terribly tough because as I told you, the first time you had to get everything lined up tickyboo, but now you had to get the two of them lined up. And it’s just that they keep jumping around with all these electric currents, and we had a very slow optical spectrometer. We never took the time out to set up a photomultiplier which would have made life trivial. We were doing it the hard way with a late 19th century spectroscopic plate technique just because that was the equipment we had. We only had a thousand dollars to spend.
I see, so photomultipliers were partly ruled out just by their cost?
Well, yes, and the time and machines to set it up and we were in a hurry. That sort of stuff. And we didn’t have the spectrometer for it. Our entire work was done with an 1894 Hilger Spectrograph! We didn’t have monochrometers and things that would have made life so much easier. We had what was lying around in Wilbur Peters’ lab. I think we made rather good use of it.
That’s very interesting.
Bell Labs was dripping with equipment. I’m not saying that out of jealousy, because it turns out, you can get an awful lot more done sometimes with less equipment because you’ve got to think instead of dress up a lot of equipment. You know, if I had wanted to, I could have found the money to get fancy spectrometers and photomultipliers and all that stuff. They had it around. But the plates were all right. But it was such a tricky experiment. We kept doing it and we got only one plate, one photographic plate that showed clearly the harmonic effect, the mixing, and published that, and that was the last mixing I ever did. We established that. We predicted in that first Letter three effects, optical rectification, mixing, and harmonic generation, and after we did the mixing and rectification, I said, enough’s enough, and I went on to other subjects.
I mean, I did a little more work in nonlinear optics to wrap it up, but after doing that I got interested in other stuff. Something for which Willis Lamb has never forgiven me. He’s always been angry at me that I didn’t stick with nonlinear optics. You know, I took Gaby’s remark seriously. I had a lot of other ideas. I communicated them to young colleagues, and my name appears on a few other papers, deservedly, sometimes just as “We’re grateful for discussion with Professor Franken,” but by 1963, I was looking for quarks. I was flying airplanes in thunderstorms to look at clear-air turbulence. I’ve always tended to do that in my life. If I don’t have anything more to say on a thing, I’m not going to spend a lifetime saying it. I’m only here for 60 or 70 or 80 years, and gee, there’s so much I want to do! I’m not saying that as if to say I’ve made my complete peace with myself. But on that point I have. Yes, it is true, if I had stuck to physics and done nothing else, I might have come up, deservedly, with a lot more peer recognition than I’ve had. So I’ve given up that. I’ve got other things in return. I’ve had experiences — there are damn few physicists that have flown airplanes into the peak of thunderstorms over Nebraska, that have boiled away tons of oysters to look for quarks, and run the largest research agency in the country, and — I’m having a ball. And I’ve given up something for that. I only work on a project as long as I really have an intellectual erection about it, and then I want to go off and consummate other events. So that’s just a difference in style. I don’t mean that critically. Bloembergen has stuck to his last, in the sense of shoemaking, and has been appropriately and justifiably rewarded for it. I just, for myself, have had a more interesting life. I’m not saying Bloembergen should have done what I did. But I am saying to Willis, “Hey, Willis, don’t blame me because I didn’t do what Nico did.” That is, stick to something and do it and do it and do it. It takes all kinds. I’m one kind, Nico’s another. I had one interesting experience I can tell you as an anecdote, with Nico. I’ll bet with anyone. I’ll debate with anyone. I’ll hold a discussion with anyone at a conference. I’m not absolutely sure that I’m right, but let’s argue about something. Nico, never in my life have I seen him debate anything in public that he was not absolutely sure of. He’s not a gambler.
We had a small conference, about 30 of us, very early in the game, down at the Army Research Office in Durham, and I think I was chairing that first session. Nico gave a talk. It seemed obvious to me that Nico had made a mistake, so I rushed in and he argued back. And I argued with him for going on half an hour. And I was saying to myself, “Franken, you’re wrong, because Nico’s arguing with you.” I mean, I couldn’t see why I was wrong, but I knew I was wrong because Nico was arguing. And I was wrong. In all the 25 years I’ve dealt with Nico, he made one big mistake. I mean, it was a mistake in a paper he wrote, a paper criticizing one of my pronouncements or results, and he made an error. And I debated, let the son of a bitch publish it and then I’ll write the Letter that contradicts — instead I called him up and said “Hey, Nico, you can go ahead and send that in, but I think you’d better —” He’d already sent it in, and sent me a copy of it. I said, “If you didn’t catch it, you must want to,” and I explained why, and he immediately saw he’d made a mistake and said, “Thanks very much,” corrected the paper. I mean, he just hates to make a mistake. Willis hates to make a mistake. Now, you’ve got to break eggs to make omelets. I mean, I hate to do it. I published two very wrong things in my life. One was — and Purcell was the one who caught it — one was on the photon rest mass and the other was on the electric dipole moment of the neutron. I made a mistake in not one but two papers, in the 30 years I’ve been publishing papers. But it’s never ruined me, I haven’t felt like shit. I made a mistake. A lot of people learned a lot of good physics because of those mistakes, too, because they stimulated about ten other papers. I made a mistake. It doesn’t bother me. I think the thought of making a mistake in print absolutely terrifies Nico and Willis and many of my colleagues. It doesn’t terrify me. I don’t want to do it anymore. But if it happens one more time, well –- [break]
I asked you in question 9, your contracts seemed to be AEC contracts.
We’re skipping 8.
I’m sorry, that’s my mistake.
OK, let’s see, 8 — We’ve identified the major actors.
Yes, we have spoken quite a bit about them. I want to know if I’ve left anybody out, why don’t we look at it that way?
We probably have, Joan, but I’m just not — Nothing leaps to mind. I mean, Carol [?] one of my former students was working at Bureau of Standards [on nonlinear optics] very early on. Let me not cloud it up, because there was a lot of work going on. I could say now that in my memory — going back a quarter century — that of the six major actors, certainly four were at Michigan, Harvard, Ford and BTL. Who were the other two, I don’t know. I mean I just don’t recall. But I would say those four must have been amongst the top five or six or seven working, but many people were working on nonlinear optics. It was a violently active field, as you know.
OK, let’s go on then. This is just a matter of curiosity to me, why you —?
Oh, number 9, that’s very easy. I had AEC support. That is, when I went to Michigan in 1956, I wanted to start up an atomic physics group, and I made proposals to ONR and AEC, and AEC picked it up, so I was an AEC lab.
So they just went on with that.
Yes. There was no significance in terms of military versus —
What group was that in AEC?
That was George Ragosa’s group. It was out of Germantown. I forget, I think it was called the Extra Nuclear Physics Research, of the research division. Oh, [question] number 10. We did a moon ranging experiment. Unbeknownst to us, Smullins at MIT was doing it, and we, Trion supplied the laser, and we did actually get an echo from the moon, with very poor signal-to-noise, I think prior to Smullins. Not worth publishing. It was obviously an experiment that could be done. I mean, when Smullins announced his result and had better data, he just happened to have had — I think he’d agree with everything I’ve said — he just had a few nights of the best damned seeing we’ve had in Boston since the Year 1, and we just had wretched seeing in Ann Arbor. It was really — we had enough light to do it and he had enough light to do it, and he beat us to it. Fair enough?
This was part of a whole program that you were thinking about, bouncing the light off satellites and testing atmospheric effects, did that ever get off the ground?
Well, a lot of it did, and I collaborated with Carroll Alley and others on the moon ranging experiment and the retro reflectors, that was finally done. I became an elder statesman pretty early in the game, because I really was more interested in some of the other fish I was frying in the sixties. On the moon-ranging experiment, we got properly beaten by MIT. They had basically the same instrumentation we had and they had a few nights of really good seeing, which made all the difference in the world, and they got unambiguous data before we got unambiguous data.
Well, good. The next question is one of Seidel’s, and maybe we should just leave it, for him what do you think?
I think it would be easier to handle it that way, because I was very much involved in that. I was the Devil’s Advocate. Keith Brueckner and Charlie Townes were the devils, or rather the angels, and I was the Devil’s Advocate, along with a man, John Atwood, of Perkin-Elmer.
I’ve heard his name a lot recently.
John and I were the two Young Turks at that summer study meeting, a voice in the wilderness saying, “Hey, you guys, you’re full of shit, you can’t do that!” But that might be — now, where is Seidel? I know him, but I don’t — But you can tell Seidel, I can talk with him a good long time about that 1963 event, and some of the material is in fact amusing. OK, 12 — …OK, Joe Jenney was one of my students who did the clear-air turbulence project. Most of these other names, I know. The only projects that I had much interaction with was, measurement of laser output by light pressure. We looked at that but it’s very difficult to do. It’s a dumb idea because there’s so many other ablation effects that overwhelm it. I did a lot of work on comparative studies of laser and radar systems, with Joe Jenney and others not mentioned. By work I mean thinking and analysis and so on.
So what was the organization of this now? Were you a kind of a consultant there or?
The Institute of Science and Technology was the umbrella organizational structure of the University of Michigan, under which Willow Run Labs exists, under the aegis of which various projects were sponsored. I had a close relationship with them. I was on the director’s executive committee that decided on awards, and it was pretty much kind of a miniature Advanced Research Projects agency within University of Michigan, then, with seed money to get things started. It would be like the office of an aggressive vice president for research in the university.
You would know what was going on.
Yes, but these names all ring a bell, but nothing startling comes to my mind. Number 13, no relation to Emmitt Leith’s work on holograms, except admiration. “Laser-radar [for clear-air turbulence], what role did Lear-Siegler play”? OK, to me it was an interesting project. In a nutshell, I was speculating that we could detect clear air turbulence with laser radar. Clear air turbulence was then in the early sixties, a very serious problem for commercial aviation. And it had really quite tremendous safety as well as commercial implications, because at that time United Airlines, for example, re-routed an awful lot of flights on the suspicion of clear air turbulence over the Rockies, which was very expensive. When you’d re-route a flight, you’d burn up another $100,000 of fuel or something. So it was an important problem, and we’d had a number of crashes due to it. So my speculation was based on the following logic. We know there is particulate matter all through the atmosphere — water droplets, ice droplets, dust and what have you. We also know that clear air turbulence arises always from the intersection or interaction of two or more air streams. There’d be no turbulence if there wasn’t that shearing or intersection. I was speculating, there might be a characteristic signature from the optical scattering from this particulate material, that might be characteristic of clear air turbulence. Because I know the scattering exists. There’s particulate matter, lasers are powerful radar, there’s scattering — So that was the whole idea of it. Getting that protect funded was very difficult, I remember I went to FAA. The reason I got into that was I went to Yale on sabbatical in 1963, nominally to finish off a book on advanced atomic physics I had taught the course a couple of years at Ann Arbor. It was a good course. And one of my students, Jim Jordan, had taken excellent notes on it, and all I had to do was edit the notes, polish them up, and put Frankenese back into them, and I’d have a book. And I already had initial reviews, very promising, the field needed it then. So I went to Yale nominally on sabbatical to write it. I sat down that first day, and I just didn’t feel like writing. I’d always wanted to fly an aip1ane, so I made myself a promise, I’d call up the airport, and if I could get a lesson that day, I’d take a flying lesson, otherwise I’d start the Goddamned book. There was a cancellation at 4 o’clock that afternoon and I took my first lesson, and what I did on my sabbatical was learn to fly. And I still have a folder somewhere labeled “Damned book,” with a contract with McGraw Hill, with dates I think have gone past. Well, like most physicists, here I’d wasted all that time learning to fly, I had to do something with it, and that’s one of the reasons I went into clear air turbulence, to combine what I knew about flying with what I knew about lasers.
Was this a very big project, or a small project?
I think we finally got our money from ARPA. A several hundred thousand dollar project. It was not a trivial one. But I remember the frustration of trying to get this funded by FAA. I kept saying, “I can explain the rationale on the back of a pay envelope, a notoriously small document —” And I got back a request from Washington, “We would look favorably on this, could you send us about 20 pages of calculations?” I was asking for $200,000, that should take at least 20 pages of calculating. It got me so pissed off, what are you talking about, 20 pages of calculations? Let’s talk about the physics of it. Anyhow, I did get it funded by ARPA and the idea was just as I expected. I had a graduate student named Joe Jenney, and he did a beautiful job running that project, and we got a Convair out of the Army and we furnished it and put laser radar on it and flew over into violent thunderstorm areas in Oklahoma and all. We were able to prove unequivocally that it was a bad idea. And it cost about $300,000. Then the Air Force decided they had to re-do the experiment. They spent three million dollars, built a wind tunnel, did it all wrong, and what they found for three million dollars was, if you take a wind tunnel, and you blow a hell of a lot of air down it, you get a lot of dust. That’s all they learned. The experiment that was done by us, with the smaller [budget] — you can go out and try it, and it turns out, you do get a lot of echoes, but the false positives are too great. That’s why it’s a bum idea. There is a pattern that you get of radar echoes in clear air turbulence, but it is not possible, at least in the arts of 1965, maybe it would be today, to distinguish that from things that are harmless, and so you’d have too many false positives and the red bell would be ringing too much and it’s no good. Now, the problem has disappeared, because the forecasting of turbulence is now good enough so that they don’t need the cockpit detector. So it’s a case where the problem disappears. I lost interest in it. I was amused to see that for $300,000 we could prove that something was asinine that some other people wanted to spend three million dollars proving was asinine.
This is really going, to be the final question, the second number fourteen. Because the other questions are all Seidel questions.
Are we doing pretty well on schedule?
Yes, we’re going to be just in very good shape. You can even write a few letters before lunch.
It’s a pleasure to do this. We can go look through my files, you can see if there’s anything of any interest. OK, “How did you become involved in the Gould patent cases, do you have depositions, legal records,” oh boy, yeah! How did I become involved in it? I was asked by Gould — if I can, — well, let me stay absolutely on the record, that’s easier for you, — OK, on the record. I don’t remember the exact dates. I was approached by either Gordon or his then attorney, whose name I forget at the moment, in the mid-sixties for a deposition. This was in an interference that Gordon had with Schawlow-Townes, a patent action, this was, I think, that celebrated interference. Keegan, that was the lawyer’s name. I guess Keegan called me and asked, would I be willing to give a deposition, and I said, “I don’t know, because I know Gordon, I know Charlie, and I know Art Schawlow, we’re all good friends. I don’t want to get in a personal contest with them.” He said, “We’ve got a problem. We need to have a witness that is willing to testify to both notebooks.” It was a very important legal point. There was the Townes notebook and then the Gould notebook. The Bell Labs folk, quite wisely, because they were in this not to play store but to win, had witnesses testify on the Townes-Schawlow notebooks and say that they had more than adequate disclosure to build a laser. No question about it. And they had another witness, different person, testify on Gould, and say, no, he doesn’t tell you enough about it and so on.
Now, the rules, the evidentiary rules in patent litigation, just like any other kind of litigation — the witness can only be cross-examined on what he testifies. So it was never possible to have one witness be forced to testify on both documents, and say, “OK, you’ve read both documents, now tell us why this one is better than that or worse than that.” The guys who testified that Townes was sufficient could only be asked, “Why did you say that?” They couldn’t be asked, “Is it more sufficient than Gould’s?” because they hadn’t testified on Gould’s. So Keegan explained that to me and said, “I need to have a witness who was around at the time, can serve as a fact witness, was expert the field,” as if anyone could be considered expert before the field developed,” and who has no financial interest in the outcome of the case. I said, “Well, I can understand that.” I worked with Keegan for a while, and we could only identify two people in the United States who met all three conditions. One was Willis Lamb, who was in Italy at the time, and would not have made a good witness, Willis does not like testifying. It’s very difficult — when you’re a witness, you’re in a situation where somebody’s trying to discredit you, and I wouldn’t wish Willis on anyone as a witness, you know. I mean, it’s just — I knew enough about witnessing to realize that was it.
So there was only me, and that’s why I did it. It was the same thing as, if I’m around an automobile accident and I’m the only witness, even though I’m going to miss my plane, I’ll stick around and give the data. And Keegan got to me that way. He said, “Look, I know you don’t want to do it because you love Gordon, you love Charlie, you love all these guys, but there’s got to be someone in the name of justice who will expose himself to both manuscripts.” That’s why I agreed to do it. And that’s why I’m still doing it. I’m the only one — Willis and I are still the only ones we could think of in the United States who were around in the fifties and active in the art, who are still knowledgeable on what it’s all about, and have no financial interest in the outcome. I don’t know of anyone else. So that’s why I’m still a witness in the case. And everything that I’ve told you is on the record. Now, if you were to ask me, hey Peter, what’s your real opinion on this or that? I would say, that would be off the record, and the reason is, the litigation is still going on. I will say on the record that everything I have said in the several courtrooms in which I’ve appeared, I absolutely believe is true.
Now, is there any part of the historical story, that we should be getting down at this point, that isn’t in your depositions? What I really mean to say is, I can’t think of anything that will be part of the story of lasers which would fit in here, that we haven’t talked about.
I can’t either. I can only tell you again that my affection and respect for these three men, Schawlow, Townes and Gould, is very very high, and as a matter of fact, is entirely independent of what I’m doing as a citizen. And witness. By the way, the story of this patent litigation is one of the most remarkable stories in patent history. And after you finish with the laser project, that would make a fascinating book. Dick Samuel is really the world’s expert on it, but Dick is not a good speaker and not a good writer. He’s a super lawyer. There is a young man in his firm, Roy Wepner who I’ve been urging to write it, because Roy writes well. He says, “God, I’ve got to take two years off and write it,” and I keep saying, take two years off, take one month and just do a story for HARPERS, get started.” The amount of material — it is a fascinating, in some ways unbelievable, story of high drama, because now the stakes are in the billions. If Gould had gotten what his lawyers claimed he deserved at the time, circa 1960, the patents would have expired. Now, if he gets it, the patents begin, and we’ve got a several billion dollar industry on which he will get royalties. So in terms of sheer drama…
P. A. Franken and J. F. Ward," Optical harmonics and nonlinear phenomena," Rev. Mod. Phys. 35(1) , 23-39.