Oral History Transcript — Dr. Arnold Bloom
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Arnold Bloom; August 1, 1983
ABSTRACT: Spectra-Physics; its founding; role played by John Atwood of Perkin-Elmer; the 1.15 micron and 6328A helium-neon lasers; relation with Bell Laboratories scientists; Bloom’s role at Spectra-Physics; Spectra-Physics’s transition from a technologically to commercially oriented firm; the 3.39 micron helium-neon line; consultant at Coherent, Inc.
This is Arnold Bloom in my home in Palo Alto on August 1, 1983, for Joan Bromberg’s Laser History Project. OK, question no. 1, what field were you educated in? I was educated in high energy physics and did my thesis work on the 180 inch cyclotron up the hill in Berkeley, got my degree — PhD degree in 1951. What were your main activities before you became involved with lasers? Well, after getting the degree I went to work for Varian Associates in the field of nuclear magnetic resonance. This led, to put it very briefly, to magnetic resonance with the earth’s magnetic field, from that to optical pumping and magnetic resonance in alkili vapors in the earth’s field, and from that to alkili vapors used as frequency standards.
This was the field I was working in at Varian before several of us decided to leave Varian and found the company of SpectraPhysics, Inc. Let’s see, “what was your work during the Second World War?” I was too young. I was an enlisted man in the Army, Second World War. No. 3, “Please tell briefly how you got into the field of lasers.” Well, we were well aware of the work in lasers because it really had a close connection, or we thought it had a close connection with the things we were working on at Varian which were in fact quantum electronics, as quantum electronics was and is defined. It seemed to us at the time that the ruby laser and then later on the helium neon laser were invented, that these things or things related to them had a tremendous commercial potential, and Varian at the time seemed to be suffering from problems of indecision in their management, which I won’t go into. (You can go into details with Joan if you wish) that made it impossible for Varian to do any productive work in this field, as later in fact turned out, and that we were getting into a situation where we were stagnating. So the five of us decided to leave Varian and found SpectraPhysics Inc. We were not certain, when we founded the company, exactly what we would be doing. We thought it might be magnetometers, or it might be frequency standards, or it might be masers or lasers, or something, but it would have some connection with quantum electronics.
Forman:This was as you said in September of ‘61. That you left to set up your own company. Could we go back? There was the Quantum Electronics Conference, international conference in Berkeley, early in ‘61. Spring of ‘61.
Forman:Undoubtedly you were there for that.
Forman:There was an earlier one in the fall of ‘59, New York.
Forman:Did you get East for that?
Bloom:No, I didn’t. Obviously I heard about it but I didn’t go to that one.
Forman:Did this Berkeley conference have any particular importance for you?
Oh, I think it did. Aside from hearing about current research work, there were also rumors, which people from Bell Labs did not deny, that they had gotten a helium neon laser working. You know, a gas discharge laser. And this was of tremendous interest to us, because we were working with gas discharges that might conceivably have population divergence in them. So this was quite interesting. Then of course later on a publication came out. But we knew, I think it was Bill Bennett who was working at Bell Labs at the time — essentially said, well, he couldn’t say anything, but “effectively the rumors you have heard are true.” That’s effectively what he said. So we had a fair idea what was going on. Let me elaborate on some of this, because I think it’s of some interest to know how SpectraPhysics got into this field.
SpectraPhysics started out, we actually did some magnetometer work, I think it was under contract to Goddard Space Flight Center or something like that. We built alkili vapor discharge lamps for that, and I think that Varian actually sold the lamps that were used in magnetometers and frequency standards for a while, sort of in competition with Varian. So we did some of that. There was a question about major products to get into. About the time that, I know what happened — the day before or two days before we were to quit Varian, John Atwood of Perkin-Elmer called me, it must have been 3 in the morning there because it was about 11 o’clock or midnight here, saying something to the effect that he heard about this group that was leaving and was going to work and could he talk to us? I said, “Look, we’re still in Varian’s employ,” I didn’t want to say anything. I guess this impressed him, but after SpectraPhysics was founded, we thought, well, it might be worth talking to him, because Perkin-Elmer after all had its reputation in this, so I gave him a call, and I think he took the next flight out of the closest airport or something like that — came, and we held some discussions for several days. Y
ou know — was there something that could be done? And it was decided that the way to handle this, because Perkin-Elmer was interested in the field also, but they didn’t really have the personnel that could push the research end of it — was that we would build a gas laser as a product jointly, this was 1.15 microns, this being the only transition we could work with — of which we would do the research, we would build the tubes, I believe they were going to — or maybe we’d built them, I forget — and they would supply the optics, and I think they were also going to do the fabrication of the metal parts of the package — went around it. This policy spread — a lot of contract stuff written up, where it essentially said that it was going to terminate at the end of 50 units or two years or something like that. Surprisingly enough, the project ended at the end of the 50 units, not the two years.
The only thing that the contract really did not count on was the total success of the product. And this occurred not because of 1.15 microns, but because of the 6328 transition. Now, while we were building these things, playing with them, working with them, we did some elementary spectroscopy on the visible lines, doing things like looking at the relative intensities of the neon lines as you see them down the tube, as opposed to the side of the tube, and came to the conclusion that there could well be some gain on some of the red lines in neon. So we ordered mirrors from Perkin-Elmer, who supplied us three or four mirrors whose sizes, the size of the blanks and the curvatures were such that we could not make a working resonator out of any combination of the mirrors. And I mention this because it is my firm conviction — which other people would probably protest — that if Perkin-Elmer had supplied us with the right combination of mirrors, we would have beaten Bell Labs in discovering the visible 6328 laser. But as it turned out, we couldn’t do it. We couldn’t make a resonator, and we had other things to do, so we put it aside.
Then, on the trip back to Norwalk, Connecticut, we heard about this. John Atwood was always well tied in to the local rumor pipeline, so he’d heard about it, and he had some connections with Bell Labs, they were supplying him with equipment, so he was able to ask favors. One of the favors was, could we see Bennett’s laboratory? Bennett took us in, essentially said, “Don’t say anything about this yet,” but showed us the red, the 6328 line. I think it was Earl, John Atwood and myself, I forget. It may have been someone else there. We promptly came back home, and with the right combination of mirrors, got the 6328 laser going right away. So that really rescued the product, and then from that point on it was a total success. It came just in time. Between the five of us, we had invested, by selling Varian stock and a few other things, we had invested, as I remember, a total of $150,000, which was not a large amount of money even in those days. You could never do it now. It would take at least a million dollars.
We’d been working on this thing for about 10 months, or a year, and were down, to about $20,000 in the bank account. This was totally on our own money, between the five founders. And from that point on, it went up, and to my recollection, SpectraPhysics did not go for any outside financing for at least five years. We were able to do it entirely on our own. OK, “concerning work as a laser scientist, a, how did you come to begin this particular line of work?” I think I probably just went into that. “What specific interactions with other scientists had the greatest impact on your work?” Well, Earl Bell, of course, because he was able to build equipment that I could work with. And also provide the incentive to do theoretical work. At least for a couple of years. Then John Atwood at Perkin-Elmer provided us with an in, you might say simply by knowing people in the East, people at Bell Labs and others — and for a while, I was able to make visits at least two or three times a year to Murray Hill, just to see what was going on. Things were a little guarded.
The Bell people were always wary of — they were less wary of people from universities, but people from other corporations, because of patent matters and so on, they were always a bit wary, but within certain limits, if they knew that things had been looked at by the patent attorneys and so on, they were willing to discuss things. Bill Bennett initially, a little less later, I think — Bill Ridrod — various men with whom I worked, what were others (???) nik I got to know personally, but I think not really — well, I think the interaction there was at meetings, things like that, but I learned a lot from him. John Harriot. Let’s see, who else? Cotell a little later. There must have been some other people. Various other people who I’ve met from time to time. All these people, I found — mostly the Bell Labs people. People from other laboratories I found just didn’t quite seem to have it, even the ones at Hughes. They weren’t interested in gas lasers for a long time — well, other than Bill Bridges.
Now, Bill Bridges is a separate story. I mean, because he’s done outstanding work in his field. But I’d say that these were the people I had the greatest interaction with. OK, “Were there any matters that particularly helped or hindered your progress?” I don’t really know anything that hindered our work. Or that helped. “Interaction with government committees and agencies” — no, I think we pretty much stayed away from the government at that time, other than the side work of magnetometers, magnetic field work, which was carried on essentially for bread and butter. “Did you have collaborators?” OK, Earl Bell, Bob Repple. In the early days everyone took a hand in it, even Herb Dwight who was a businessman would on occasion come in and turn something on a lathe to help us out. The work was divided. If it had to be done, someone did it. “What stance did the head of your laboratory or department chairman take towards this piece of research?” Well, there were five people involved. You know, there got to be a few more later. You can’t really say there was anything like that. It was sort of a very small committee, just forging ahead. “Institutional resources could we command?” Very little. All we could do at first was get highly reflecting mirrors out of Perkin-Elmer, and even those were of very uneven quality.
They sent us a lot and some of them were just great and some were poor. And it took, it was a number of years before SpectraPhysics decided to build their own (?) facility. “Did you publish your results?” Yes. As often as possible. We felt this was one of the best ways to establish prestige for the small company, as well as for ourselves. “Patent them?” Yes. We had a feeling patenting was a bit of a nuisance but it had to be done. “Present them at meetings?” We certainly did that too. “How did you choose a suitable journal?” Well, mostly PHYSICS and later on OPTICS. I went to an Optical Society Meeting, I think it was the end of ‘61, just after SpectraPhysics was founded, a meeting in Los Angeles, and I came away feeling that this was a outfit full of fuddy duddies, they were old people, really of no interest, and they weren’t interested in lasers and I wasn’t interested that much in classical optics. It just didn’t seem the right way to go.
Now, it’s rather amazing that the Optical Society itself really turned around in a period of a few years, and got oriented to the dynamic organization that it is today. “How has your own research in lasers been funded?” Primarily it was entirely company funds, in many cases supplied by ourselves. “How has this changed over time?” Well, you know as companies grow, they get outside financing. It’s a little hard to say, but in my case it’s always been company supported research. I think we pretty well stayed away from government research because it very often turns out to be counter-productive for small outfits. Anyway, it’s all been company-sponsored work. “Did you participate in the commercialization of your results?” I did not really get involved in product development. I did get involved in publishing papers. I wrote a series of things called technical memos or technical papers of some sort. I think there were about five or six of them, on various aspects, and these were published privately by SpectraPhysics and got very widely circulated.
It’s rather unfortunate we didn’t publish them in the review journals somewhere, but we never did, and I think that people still refer to them in the literature occasionally, SpectraPhysics Technical Report No. such and such, having to do with things like resonator series, as it was understood in those days, I guess the physics of the laser action, things of that sort. I may still have some of these around somewhere. So I contributed that way. Occasionally I did some sales work of one sort or another. I even took a trip to Europe once, demonstrating lasers to various laboratories. I once took a vacation in Hawaii, and when people heard I was going there they said, “Oh, someone at the University of Hawaii wants to see a helium neon laser, so would you like to take one there?” So I did. You know, it got shipped and I picked it up with my luggage and so on and said essentially, “This is a vacation but I’m going to spend three hours for SpectraPhysics,” which paid for the trip effectively. I took it there, and I recall that Honolulu, as you can imagine, has a much more humid atmosphere than we have here — took it out of its packing case, which was full of silica gel and a few other such things, turned it on and it worked beautifully, gave a nice clean beam. So the director of the lab said, “By the way, would you like us to show you around the lab?” So we went around, spent about 15 minutes, he showed me his laboratory — came back, and the beam was full of concentric circles. It was obvious that the (?) reflection coating on the outside of the optic mirror had gone completely to pot, there was no longer an (?) reflection coating. So you learned something about the humidity in Honolulu very quickly that way. I don’t remember whether he bought a laser or not. “What were the difficulties and how were they overcome?” Well, I can tell you one night — any engineer in a small company can tell you similar stories — the night when you didn’t go to sleep because there was an exhibit the next day, you know, show and convention, where you were going to exhibit your product, and the night before, the thing didn’t work.
That was the night we learned that, for gas discharges, like helium neon lasers, you put your bellist(?) resisters as close to that tube as you can possibly get them, because if you have any length of wire in between, the discharge oscillates. It took us all that evening to discover this, but we learned a lesson. You know — the shipping department and so on comes in the next morning and says, “Gee, you’re here early!” OK — difficulties were overcome essentially by just putting an awful lot of work into them. OK, No. 5, concerning your work as a laboratory administrator. I will go through that very quickly by saying, I am not an administrator. It became fairly obvious in early stages that I was not. I never made any pretense of being an administrator, and my main contribution was, effectively, I would say, as a full time consultant, being there on the spot to discuss things, show how things could be done, and try to direct the research, which became, because of personalities, became a little more difficult later on. But as things started, there it was. OK, I’m not going into details. “Concerning your work in the laser industry, we’d like to know how you came to organize firms that you founded or —” Well, I’m not really the person to answer those questions.
A lot of stuff was done on a small committee basis initially. And sources of research information — we drew on journals, occasionally reports, occasionally rumors that we could check out, and as I said we occasionally had contacts with people at Bell Labs and elsewhere who would tell us what was going on. Main effect of the international and domestic business environment — in the early days, in the early sixties, it was very good and very conducive to a small company starting out in something like this, going up.
People were willing to buy research project sorts of products and see what could be done with this. Now, this changed about, started to change about 1969. I believe there was a bit of a recession then. About the time that a lot of engineers was being laid off, and the entire environment changed to the point where it began to reflect itself at SpectraPhysics. Partially, there was also a personnel change. Management was becoming more strictly business oriented. But it eventually reached a point where one of the quickest ways to kill a project was to say that it had scientific value. This just became a nasty word. Everything was to be oriented toward existing products or existing fields. To give another example, we got a marketing manager in about that time, that I didn’t know very well, and I was explaining some of the things I was doing like writing these technical memos and I said, “You know, I haven’t written a technical memo for a while. Would you like me to write another one, to improve(?) your sales literature?” And his comment at the time was, “Well, our main customers now are sewer contractors who use helium neon lasers for laying sewer pipes, and sewer contractors don’t read. So we don’t want your technical memo.” So that was the way things changed there.
It was sort of at that time I left SpectraPhysics, because it was becoming, from my point of view, so business oriented, I really could not find a niche in which to work at that time. Coherent asked me to come over and help them out, essentially as a full time consultant, which I had done and am still doing. And in my opinion, Coherent has a more relaxed atmosphere, although Coherent has never really pushed the research end of things, but at least, even in product development, things are relaxed, and they’re willing to look at things from several points of view and not, the point that everything has to be strictly business. OK, the main effect of the domestic — “How did you set up your in-house research?” Well, it was set up with whatever equipment we could buy or build easily. “What types of scientists and engineers did you hire?” Mostly people who were pretty creative and knew how to build things with ingenuity. The type of person who has to engineer everything right from the start, down to the last nut and bolt, would not have been successful at SpectraPhysics in the early days. That came a little later, when there was the time when they were starting to build fancy systems.
OK, funds for R and D efforts came strictly from the company. “Please describe the chief products and processes you developed.” The helium neon laser started first, initially at 1.15 microns, as a research instrument. Then when the visible laser came, we were right there, right on the spot, first one to actually market a visible laser, and of course that had a huge market initially for research and other products. Then ion lasers came around. Earl Bell was I guess probably the first discoverer of an ion laser with mercury vapor and it was pulsed. Not too useful for us, but then Bill Bridges, starting to play with the mercury vapor, discovered the argon laser. We discovered it ourselves, or Earl Bell discovered it, and then I picked up APPLIED PHYSICS LETTERS the next morning and discovered the paper by Bill Bridges in it. That’s the way these things happen. Then Bill Bridges went ahead and built the CW laser, and we got into that fairly quickly thereafter. “Obstacles” — well, there were all sorts of unknowns. I mentioned the one about the oscillations in the discharge.
Another problem was clean up of gas, simply sputtering of the neon into the walls. This caused a lot of problems, and it was essentially a question of tube design, knowing how to build cathodes that don’t sputter, and things of that sort. I was somewhat involved in that. Other people were involved too. These were overcome by hard work. It’s hard to say otherwise. Marketing strategies — I don’t really know too much about that. I did not have too much to do with marketing strategies. OK, concerning your work as a general editor and society officer — I was not an officer. I am a fellow of the Optical Society of America.
I’ve been on various committees. I’m on a committee now, about which I won’t dare say anything because it involves confidential information. I’ve been on the education committee and I’ve been on their award committee. I have been on advisory committees to the NBS, having to do with quantum electronics spectroscopy at various times, both at and in Boulder. “Tell us about controversies in the history of lasers” — I think, well, the principal milestone was the visible helium neon laser and then the argon, the CW argon laser, later on the high powered CO2 laser. Those to my mind were the real milestones. By the time the xma(?) lasers came around, I was not really working that closely in lasers, because by that time, I had started working at Coherent, and my main interest was more in, simply in the thin film modulator theory, than in lasers, though occasionally I’d work in resonators, but I have almost nothing to do with actual laser discharges now so I don’t know much about (?) lasers. Di-lasers were important. I did some work on those. So I guess those were the principal milestones. Controversies — Gene Gordon of Bell Labs and I had a controversy at one time regarding priority, in discovering the visible lines, other than the 6328 of helium neon, and he, I think at one time, claimed that I stole the idea from Bell Labs, which in fact I didn’t.
Now, I think I have a notebook entry at SpectraPhysics to prove it. It occurred to me, having studied the 3.39 micron, which I believe we discovered before Bell Labs did — If I may digress a moment, we were using quartz booster windows, which passed the infra-red. They were using pyrex, which cuts off the infra-red. So they did not see the 3.39 micron laser radiation. We discovered it in our own lab, and of course they verified it later. But in working with that and using prisms to separate it out, it became evident to me that there must be something like competition between the excited levels that were giving rise to visible transitions in neon, and the use of the prism, could, might be able to get around this, and we might be able to see some of the other lines. So I set this up one evening, just using the existing setup that Earl Bell had set up. There was a long, three meter long laser, and sure enough, I saw these lines, and rushed into print the next morning. I think we can find this is PHYSICS LETTERS somewhere in ‘64. And then I got all these phone calls from Bell Labs, or something like that. I forget why they — I don’t know why they didn’t see it.
I think they just didn’t push the project. They’d been thinking about it but they just didn’t get around to doing it. Sorry — so. Obviously they did it right away after they saw my paper. They obviously saw these transitions. I think that’s really the only controversy of that sort I’ve been involved in, and Gene and I are sort of — I shouldn’t call him Gene, Dr. Gordon — just sort of on the outs for a while, but there’s really no competition now, we’re doing such different things. Occasionally he writes me about one thing or another. I consider it a real scoop that we were able to beat Bell Labs at anything.
Forman:I should think so.
Bloom:This doesn’t happen too often.
Forman:You certainly had other things to worry about.
“Participation in funding agencies,” no, I have no input to give on that. OK, “Other comments about your career and the field of lasers and its applications” — as I said, SpectraPhysics never got involved in military applications that I know of, at least not while I was there. At Coherent, that I’ve been working in connection with, although not always as a full time employee, since December of 1971, has never been interested in that either, which suits my purposes entirely. Now, my career in lasers really ended when I left SpectraPhysics. I was involved in dilations a little bit, and then I got involved in theoretical design of (?) and that’s basically what I do now. Oh, I deal in personal computers these days. Two years ago I would not have believed you could put these optimization programs and other such things in a small computer, but you can.
Two years ago I was doing it all at Stanford on a large IBM computer. OK, “field of lasers and its applications,” well, something that I had thought, when we founded SpectraPhysics, and it turned out not to work, obviously, was that SpectraPhysics was going to be a relatively small outfit but it was always going to be at the cutting edge, to use the cliche, and that as products became more standardized, more to the point where you could design them from engineering nomographs, that this sort of thing ought to go to more established companies that were more interested in that sort of thing, and SpectraPhysics would then go on and do other things. Well, it didn’t turn out that way. It turned out, about the time that Randall(?) left the company and Bell left the company, and effectively the business administrators took it over, that we were going into things like helium neon lasers in a big way. Well, by 1970 everyone knew how to build a helium neon laser. You could do it effectively from nomographs. You knew that there were certain relationships between the tube diameters, the tube length, the appropriate gas mixture to go into the tube for those parameters, and the amount of power you were going to get out, and the size of the mode, and all these things were now standardized. It was almost like building a transformer. You just go to the charts and you do it.
So, you know, these things had no scientific interest. And argon lasers were getting close to the same way. Now, I would have preferred to have just seen SpectraPhysics sell this off to someone else, but they didn’t. They decided effectively to drop all the other stuff and concentrate on this, as a strictly business venture, so about 1971, I effectively discovered I’d come into the office and have nothing to do, so I left. Let’s see, what else. That’s probably about all. All I can usefully say, unless someone prompts me on things I’ve forgotten. OK, “list the career steps” — schools I attended, I went to the University of California at Berkeley, got a BA in 1947, having served a couple of years in the Army, went to Westinghouse in Pittsburgh for a summer, turned out to be interesting, at least learned something about corporate politics, if I didn’t learn anything else. At least the politics were interesting. So I had some exposure to industrial laboratories. I got a Ph D in 1951 in high energy physics and then went to Varian and started working in nuclear magnetic resonance, and —