Gordon Gould – Session I

Bromberg:

This is April 8th and this is Mr. Gordon Gould I’m speaking with, and Ms. Marilyn Appel is also here. My name is Joan Bromberg. We’re going to talk about some of the oral history phase. So we want to talk about how it is that you came to be interested first in the optically pumped maser that you were telling me about that you invented. And so now I would like to go back and see how you came to that point, that invention.

Gould:

Well, any invention requires putting together materials that are already in your head from somewhere, and for the previous 20 years or so I’ve been stuffing my head with what later turned out to be the bricks and mortar for several inventions including optically pump maser. I might start that I always knew I wanted to be an inventor, even back in high school. And when I went to college at Union College between 1937 and 1941, I got very interested in optics. I had a professor there who was himself very interested in optics, and he set me onto projects such as all night exposures of defraction phenomenon and so on, so that became my favorite part of physics.

Bromberg:

Do you remember his name by any chance? No.

Gould:

In the summer of 1941 when I graduated from Union I got a job, my first job with the Western Electric Company. It was in their physical testing department associated with a manufacturing operation they had in Carnie, New Jersey, of all places. And during that summer they decided that I might be a good candidate to stay on at Western Electric, so they went through a process by which they introduced promising young people to the various levels of management. I remember being interviewed by higher and higher executives, and funny they had a rug on the floor, and then they had a secretary out front, and I finally got up to the vice president in charge of that plant. He was 11 rungs up from me, and I asked myself, “Could I possibly want to spend my life climbing that ladder? No way.” So in that fall I went to Yale and began graduate work there.

Bromberg:

In what field, what part of physics?

Gould:

Yale happened to be in specialized in optical spectroscopy, which is one reason why I chose it. They had some unique equipment for that day in the way of spectrometers and other optical equipment. So for two years there I was doing experimental work, and taking courses that would lead me to a Ph.D. in optical spectroscopy.

Bromberg:

Do you remember there people you were working with at all?

Gould:

Now you asked me who some of my professors and other people were at Yale.

Bromberg:

Something of that and of what kind of problems you worked on, what the environment might have been for that study?

Gould:

The head of the Department of Physics was Professor Watson, and other luminaries who were there at the time were Henry Margenau; Lars Onsager, he got a Nobel Prize eventually. I just can’t remember any more names at the moment, but they’ll come to me later.

Bromberg:

Was this just course work at this point or you were already doing research?

Gould:

No, I was doing laboratory work, but not working on a particular thesis. And I would have launched into a thesis about 1943 or so if it had not been for the War. There wasn’t enough teaching to be assigned to the graduate students to keep them all out of a draft, so a number had to leave, including me. Dr. Watson said go to a certain address in Manhattan and knock on the door and tell them I sent you. And low and behold, it turned out later to be the Manhattan Project, and I worked there for the rest of the War. So graduate work was cut off at Yale for me and only a number of years later did I decide I had to go back to graduate school to learn not to be a good inventor, and I did around 1949 start to take courses at Columbia.

Bromberg:

Tell me, did the work you did during the War, did that feed into the kinds of things you eventually found yourself inventing, or was that just...?

Gould:

Well, there was a richness of technology and things going on in the Manhattan Project, but not particularly in optics. My first job there seemingly had nothing to do with the A-bomb. It was that the equipment required to separate the isotopes of the uranium was a vast structure of pipes and pumps and all kinds of things, was many, many miles long, which had to be absolutely vacuum tight. Nothing like that had ever been done before. It wasn’t even known whether it’s possible. Vacuum technology was really at its infancy then. A. O. Neer [?] invented the helium leak detector just for the purpose of helping to get that vast diffusion plant vacuum tight. So I became an instructor in a class to teach vacuum technology to people, and in the course of teaching it I learned about it, too. And that, of course, is needed for any kind of equipment or experiments working on gases. And so later on, of course at Columbia where I worked on atomic themes for thesis work, that came in good stead, but it’s more of a standard sorts of things that a student would know about now if he was a gaseous physicist, but not then. Interestingly enough, there just weren’t enough trained people around to man that huge project. So the fellow who was in charge of setting up his vacuum school said to his superiors, “I’m going to go out and hire a dozen bright English majors, and get them in here and teach them.” And he proceeded to do that. And they proved, most of them, to be quite adept, and they went around leak testing all the equipment as it was being put together. One of those people was a young woman named Glen Fulwater, whom I married the next year. [Chuckles]

Bromberg:

So she was a student. I mean she originally came in as a student of yours.

Gould:

Well, this was in the Manhattan Project, and in a sense she was a student, but — Okay. Yes she was a student in a sense, but she was not a student in college. She had graduated from college as English major.

Bromberg:

No, I mean she was student in this special course.

Gould:

In this special course, right. And I suppose of course lasted a couple of months, and then they were off doing their thing. She was my first wife, although I met my second wife previously at Yale.

Bromberg:

Well then, from the special vacuum work, what did you go on to do? By the way, I might say that very often what I’m finding is that war completely reoriented a scientist. Well, the way, for example, it looks as if Dickey [?] might have been going on the path of nuclear physics, and then sharply veered into micro radio. And I’m rather interested to see the kind of impact, you know, as you come in with your optical spectroscopy interests, the kind of impact, if any, this has experience has given you.

Gould:

Well, I didn’t follow the direction that I might have from having worked in the Manhattan Project, which I suppose might have been nuclear physics or something, but that was not the thing that interested me the most. And even though I didn’t do any work in optics at the Manhattan Project, later when I went back I was interested in optics. But anyway, the important thing during those years was the experience I had with optical spectroscopy at Yale, and not just theoretical, but hands on experience with the techniques of manipulating light. And then when I went back to Columbia, there was an entirely different emphasis there. The Columbia radiation lab was one of the laboratories that were set up during the war to work on radar. There were two big efforts that involved physicists during the war, development of radar and the development of the atomic bomb. At Columbia, microwaves was everything, and the Columbia Radiation Lab, which had been set up during the war to work on optical radar, continued to do some work related to defense needs, developing better magnetron oscillators and such devices. But the professors managed to make use of the existence of that laboratory, and the support that it got from the Defense Department, to have students doing research, basic research unrelated to radar.

Bromberg:

Now you went there. Did you start immediately? There’s a little gap there. We will come back to it.

Gould:

Yes. The little gap is that I went out and got a job at a company called Semen Bache and Company, which made mirrors. I deliberately got a half time job so I could spend the other half working on inventions that I had in mind. I managed to get the use of a laboratory over at New York University in exchange for setting up the vacuum equipment that the professor wanted there. I struggled rather unsuccessfully for several years without accomplishing very much. One of the projects I was working on was a method of making synthetic diamonds that I thought I could do.

Bromberg:

That’s a very interesting period though, I should think.

Gould:

But what I learned was I didn’t know enough to do these things. I guess my bent or interest was not towards such practical inventions as making a new safety pin or something like that. I got myself involved with things that had deep physical theory associated with them, and if you’re going to do that you better know all there is to know about it.

Bromberg:

You want to mention anything besides the diamond project while we’re on the kinds of things you were concerned with in that period?

Gould:

Well, another somewhat practical invention was a contact lens. Contact lenses had just been invented, but they weren’t easy to use. You couldn’t wear them more than an hour or so at a time because the cornea of the eye would get foggy and you couldn’t see through it. So I figured out what the problem was, and how to do something about it. Oh, I should mention, by the way, the cornea is one of the few, maybe the only organ in the human body living that breathes directly into the air since there’s no blood vessels there, and therefore by putting an impervious contact lens over it, you starve it of oxygen. That was the problem. So I figured out a design for a contact lens that would enable the blinking of the eye to wash fluid tears under the contact lens — make the eye blink a pump. Then I went around to the company that was trying to get contact lens going, and tried to come to a deal with them to take up my invention. They were interested, but I was so naive it wasn’t possible for us to come to terms. I didn’t want to tell them what the invention was, so that’s not a very good way of selling yourself and the invention. And after some inconclusive discussions, that never came to anything.

Bromberg:

I find this a fascinating story. I don’t think inventors in this period — I mean I think of Edison, you know, setting up to invent...

Gould:

Actually Edison was one of my heroes. Although today, as you say you think of inventors as physicists or electrical engineers or something, still there’s an element of that Edisonian thing in anybody who calls himself an inventor, and in particular in me.

Bromberg:

It was a very Catholic view you were taking towards the various kinds of things.

Gould:

Well, I was interested in that contact lens thing in particular, because I had worn glasses since I was five years old, and I wanted to wear contact lenses but I couldn’t. So it was as simple as that. Incidentally, Edison is thought of as the inventor, but he actually discovered some important basic physical phenomenon, too. For example, he discovered the thermal emission of electrons, which became the basis for filaments for vacuum tube tryouts of other vacuum techniques. He discovered it while he was trying to make a light bulb work electrons came out of this hot wire. But he was an inventor as distinguished from a scientist. He didn’t pursue that scientific discovery. What is the difference in attitude? Well, to me I never was interested in studying something just for its own sake. I was not drawn, as some people are, and fortunately there are people who are interested just in knowing how things work because we certainly wouldn’t have any technology at all without… there wouldn’t be any science if it weren’t for those people. But for me, there had to be an important application at the end of the road for me to really get excited. Thus, I enjoyed the physical things I was doing at the laboratories at Columbia during the years I was working on my thesis, but it didn’t really get a hold of me the way the laser did when I thought of it.

Bromberg:

Well, then how did you come to work in the molecular beam group at...?

Gould:

Well, as I said, I felt I didn’t know enough, and it certainly was true. And so I began to take courses at Columbia, and finally matriculated in the physics department there to get a PhD. And Professor Polykarp Kusch took me on as a graduate student, which meant I would work on some project that was of interest to him.

Bromberg:

Did you choose him, or was he the best from your point of view of several, or what was going on?

Gould:

Well, I can’t remember exactly how that came about. Maybe we chose each other. There’s always a certain amount of interaction among the students and professors, and I think we both felt that I liked the idea of working under him, and he must’ve felt that I was a student that he would like to have working on one of his experiments. I can’t remember precisely. But in any case he was the one that selected what I would work on or I agreed to work on what he suggested, which was to do an atomic beam experiment to measure the hyper-fine splitting the energy difference between two sub levels of an atom within a particular electronic state, having to do with nuclear interactions with the electron, on the thallium atom.

Bromberg:

Were you interested in these nuclear interactions? I mean these whole questions of the way in which [inaudible]?

Gould:

Not really, no. But the experimental work was interesting, and I liked doing that. The problem that was said to me — The measurements of the hyper-fine splitting had already been done for the ground levels of most of the atoms that could be detected in these machines, so Kusch set me the task of trying to measure the hyper-fine splitting in the first excited metastable level of thallium. And the problem was to get enough atoms into that level to be able to measure them in their existence in the beam. I won’t try to describe an atomic beam machine, but it’s one that manipulates the paths of atoms moving down the machine by magnetic and electric fields, thereby measuring energies by way of noting the frequency of an oscillating electric field that could cause a transition from one state to the other. And I worked and worked on that thing, and I tried two different techniques for getting the population up there, and I just couldn’t get enough to be able to detect enough of them to make a measurement. The detector needed for detecting the thallium atoms was particularly noisy, and I could never fish the signal out of the noise.

Bromberg:

Is this something that was going on with a whole bunch of graduate students interacting with each other, and so on?

Gould:

Oh, yeah. There must’ve been 10 different atomic beam or molecular beam machines at Columbia, and this was a specialty of Columbia Radiation Laboratory. It was all started by Professor I. I. Rabi, one of the many Nobel Prize winners that came out of Columbia.

Bromberg:

So you’d go to speak to people and say how are you doing this, and I’m trying that, and so on?

Gould:

That’s right, that kind of thing. So everybody had some familiarity with the other experiments that were going on or thesis, and in particular I was quite aware of the first maser demonstrated at Columbia, because that was done in a laboratory right upstairs from mine. And that, of course, was done by students of Townes.

Bromberg:

I would like to know whether there were any people with whom you were in especially close contact among the, in the beam group for example, just this kind of thing? Just to get an idea, again, of the kind of...

Gould:

Well, one of my closest companions there was Peter Frankton, who’s now head of the Optical Institute at the University of Arizona, and we’re still good friends. And then there were numerous others including Gordon, Zager and Townes, who did build the first maser. I knew them, but they weren’t particularly — I liked them, but they weren’t particularly close friends of mine. Jimmy Gordon, later at Bell Labs and did work with lasers later on, happened to be a fellow student of mine at Scarsdale High School back in 1936 or ‘35. No, I guess he was a fellow student of my brother’s, and his older brother was close to me. That’s right. But anyway, I knew him from way back when. Then Alan Burman, who until recently was the head of the Naval Research Laboratory, and now he’s head of the Rosenstiel School of Oceanography in Miami. Did you now that?

Bromberg:

Yes, I did. I just found out when you did.

Gould:

I got to know many other people there, such as William Bennett and Ali Javan, who were fellow graduate students of mine, and who later worked on the helium neon laser at Bell Labs.

Bromberg:

Were Bennett or Javan in the molecular beam group, atomic beam group or...?

Gould:

No. Javan — By the way, Townes was in a sense the father of microwave spectroscopy. Atomic beams machines were a particular kind of device for making microwave spectroscopy measurements, but there were others, and Townes’ students were working on other techniques. Bennett wasn’t even working on microwave spectroscopy. He did his thesis on positronium, sort of more of a nuclear physics type program. And the other professors, that place was very frugal and very stimulating in all kinds of ways. Just to tick off some of the people who were on the staff, Louis Lamb, who got a Nobel Prize?

Bromberg:

And he was there while you were.

Gould:

He was there. Townes, of course, and Kusch got Nobel Prizes, and T. D. Lee got a Nobel Prize there. He was the one that first predicted the parody...

Bromberg:

Was he also there when you were?

Gould:

Yes, he was. I took a class from him among all the others. He was an exceedingly bright person. And of course, Rabi, who started the atomic beams worked there.

Bromberg:

He was department head, I think.

Gould:

And was head of the department. Well, there was a rotating of the department. But he was a guru in the lab. He was there first before all these other people, and he is the one that really instituted the Columbia Radiation Laboratory. Well, so as I say, I was trying to get a population into the metastable level of thallium and not having much success, and back from Europe comes Dr. Rabi, who had just attended a conference in optical pumping in France, and he got all excited about that. It was a new technique in optical work, which differed from older optical spectroscopy techniques in that by exciting atoms with light from a lamp of those same atoms, you could get sufficient power into a gas to get ponderable populations into upper states, and do spectroscopy in those upper states. So he said to me, “Why don’t you try this to populate this thallium metastable?”

Bromberg:

He was that closely in touch with the work that you were doing that he...

Gould:

Well, he knew something about all of the experiments going on in the whole of the laboratory. Yes, he did keep track. He kept track enough to know that I wasn’t getting anywhere, or maybe Kusch talked to him about it. I don’t know. At any rate, a suggestion from Rabi was in order to try this thing, so back I am with optics again. And nobody else was doing anything using optical techniques at the whole Columbia Radiation Lab.

Bromberg:

I’d just like to pursue this point a little bit, because I think it’s a major point. I read the other day a paper Kestler [?] that...

Gould:

He was one of the people that started that whole trend.

Bromberg:

Right. Suggesting all this in 1950. So this means really that there was a real time lag before it began to be taken up, from what I understand. Would that be correct? Before the news sort of reached...

Gould:

Yes. In particular, the early work using those techniques was all done in France, and it was only after that delay that people began to do things with optical pumping in the United States. I was probably the first, and that was because Rabi came from France and brought this with him.

Bromberg:

That was your first contact with the...

Gould:

With optical pumping, yes.

Bromberg:

…with via this mechanism of Rabi attending a conference.

Gould:

Right. And so I started working on optical pumping of the thallium beam about the beginning of 1956.

Bromberg:

Did you have to devise the lamps and so on?

Gould:

Yes, couldn’t buy them. I designed the lamps and the equipment to do this. I designed a cavity with a very highly reflective inside through which the thallium beam could pass right beside the lamp, and had quartz thallium lamps made to my — actually I made some of them myself — specifications. And I succeeded in getting a lot of population up into that level, and I measured that as hyper-fine splitting in the two isotopes.

Bromberg:

I’d like, by the way, if you have some papers or notebooks on that anywhere around, it’d be nice to get a hold of that.

Gould:

Where is that list? I published the results of those experiments, and I guess the first published paper that I ever had.

Appel:

It’s right on the top of that list.

Gould:

Yes.

Bromberg:

And that also tells about the devices that you had to work up to get this?

Gould:

Notice it was published, oh, it was in the Physical Review. I’m pretty sure it was the Physical Review Letters, not Physical Review.

Bromberg:

But I think that they weren’t separated at that time, but maybe... I’m not sure, but.

Gould:

Maybe not. At any rate, it was a short paper, and there was only a very brief description of the equipment, mostly by reference to previous atomic... back at the beginning of this tape, and I don’t remember exactly what I was talking about there, but it might have been that I was working still on this thesis trying to populate the upper metastable level of thallium, and rather unsuccessful, until Dr. Rabi came back from France and brought back the ideas that were being developed there for using optical pumping as a tool in spectroscopy. That technique first suggested by Alfred Caslea(?) and Brossell(?) and others took it up and started using it in conjunction with optical spectroscopy, and Rabi brought this idea back, and said to me, “Why don’t you try using this technique to produce the population you’re looking for?” And I tried it, and built an optical light box, so to speak, with a thallium lamp in it of my own design, and low and behold I was able to get about five percent of the population into that metastable state. I checked it, make the measurements of the transitions, and published the measurements of a hyper-fine splitting in the metastable levels. I remember actually that was quite exciting when I first saw that transition. After I was able to detect the metastable beam, I knew from theoretical estimates what that splitting was going to be, but the line width was extremely narrow for the transition, and I had to cover a lot of ground with these very precise microwave oscillators. And for days and days I was carefully sweeping along looking for this transition and not finding it and being discouraged. Professor Kusch came in, and we sat down, and he started wildly racing up and down through this whole spectrum. He found it in about 15 minutes.

Bromberg:

That’s actually how you get the Nobel Prize.

Gould:

Right. After I built the equipment. At any rate, that was during the year 1956, and toward the end of 1956 I realized that that same pumping technique could be used to excite a maser, that is a microwave amplifier by stimulated emission of radiation. And of course everybody knew about that because the first maser was built at Columbia University, and I think that was made to operate around 1954 or something like that.

Bromberg:

They published their first Physical Review Letter in ‘54, and then ‘55 I think with a lot of work.

Gould:

Columbia University in those days, a student could be buried there, and never see the light of day for years and years and years. The average length of time to a thesis I think was six years at that time. I’d already been six years there, and I wrote a notebook describing how a maser could be excited by optical pumping, and gave a little talk on it at Professor Townes’ invitation. But since it was not part of my thesis, I then put it aside and continued to work on the thesis.

Bromberg:

And there was no equipment associated with that, which was just...?

Gould:

Right.

Bromberg:

And you were talking a little bit about the various reasons for putting that aside, and you told me that at that point you didn’t really see that much practical use for a maser.

Gould:

Right. It was interesting from a theoretical and also from an experimental point of view as possibly a tool that could be used in spectroscopy. But practical applications say in the industrial world, no, because the amount of power was not infinitesimal, but very small, like 10 watts output. I don’t know. And the same was true of all other kinds of masers because of the small amount of energy associated with each microwave photon.

Bromberg:

Now when you looked at the maser and realized that you were dealing with low energy photons, were you already thinking well, if this could be done with a high-energy photon? I mean, do you recall?

Gould:

I can’t recall that very clearly. I must have been thinking about it from time to time. I certainly must have been thinking about it unconsciously. But I wasn’t sitting down trying to think of the laser because I didn’t know what the laser was going to be. Remember that these masers, the radiation, although it was coherent, the wave length of those microwaves is of the same order of size as the resonator, so there’s no beam associated with it, no beam generated radiation — nothing like the focusable beam of a laser. So how can you consciously try to think about what you don’t know might be? Yet there has to be some — Well, I have, through the years felt that the process of inventing things — Well, there are two different categories. One is you have a problem, and you’re trying to solve it. That’s the usual type of invention. But usually those aren’t very fundamental. And another type of invention is to have in your mind the bricks and seeds (if you don’t mind a few mixed metaphors) of some new way of doing things, but you’re not trying to solve some problem. Now this later kind of invention I think is the more important kind. It’s sort of what happened in Townes’ mind when he was sitting on that park bench in Washington when he thought of the maser. I don’t think — I’ve never seen it described — that he knew what it was that he wanted to invent. He just realized that he could make use of this stimulated emission of radiation in an apparatus, which he conceived of then. I think one’s mind, if you have an inventive turn of mind, is constantly churning through all things that are in your head, fitting them together this way and that without necessarily having any conscious goal. I know that happens to me all the time.

Bromberg:

That’s what I was wondering.

Gould:

And then at some odd moment things will click in there, maybe for the 500,000th time. You’ve fitted a lot of jigsaw puzzles together. All of a sudden they fit, and it springs into your conscious mind, “Aw, you could do that?” And that’s really what the process is.

Bromberg:

Also of great interest to identify, as far as we can, your style of inventing. I think that’s a very interesting thing to see how, because I think people do have particular styles of doing science for inventing.

Gould:

Yes.

Bromberg:

So as we talk, you might want to characterize one or another.

Gould:

You know, most people are brought up kind of suppressed as to what they can think about, and so their minds are not creating things — they aren’t allowed to create. I’m not using exactly the right word. But you have to grow up in a way where your mind has become open to new ideas and new ways of doing things. You have to be willing to look at a new idea if you’re going to think of one, and most people aren’t. But at the same time, if you’re not disciplined, then nothing useful can ever come out of such creativity. You create meaningless things, so to speak.

Bromberg:

Should I understand this to be something that you were consciously saying to yourself then? “As an inventor, I need to be open to new ideas, and I need to be disciplined.”

Gould:

No, that just happened to be the way I was brought up.

Bromberg:

I see. Then now this is just in retrospect into...

Gould:

Yes.

Appel:

Many people have asked this kind of question, so he tends to think about it more now than he did in those days.

Gould:

I couldn’t have been an inventor if I hadn’t been brought up in a family that encouraged such mental attitudes. I made a distinction between an invention made for the purpose of solving some problem or being able to do something that you really wanted to do, and an invention that seems to come out of the clear blue sky that enables something to be done that nobody even thought of wanting to do. And the later type of invention is rarer, but I think often deeper in significance. Thinking back again to this hero, Thomas Edison, he did try to do things. It’s true most of his inventions were directed towards some purpose that he had in mind before, but he nevertheless was able to think of new things that might be done that nobody had tried to do, which were not a problem. The phonograph, to conceive that it might be possible to record the human voice was something nobody had ever dreamed of before that.

Bromberg:

I guess that really occurred to me when you were making these very obvious, but to me quite moot point of the difference in photon energy between microwaves and light, it occurred to me well maybe at that point people generally began to say, “A maser in the optical region would give us high power.” And I just wondered if suddenly this kind of idea came to you or maybe we’re talking about?

Gould:

Okay, let me speak to that. When I did think of the laser, meaning a laser amplifier with a resonator around it so it would oscillate, I did immediately realize that it would have a lot of power, or could, and that you could do things with that power. And in that first notebook number one, I even mentioned some things that you’d be able to do, and that it would not be limited to the temperature that you could raise a material to with a laser would not be limited by the second law of theory dynamics at all, and that it’s beam could be brighter than the sun or any thermal body. I even mentioned, I made a calculation to show that it could raise the temperature of some material sufficiently fast to raise it to the fusion temperature. That was very exciting. That’s what caused me a couple of months later to leave Columbia to do something about it, as distinct from what I did with the optical pump maser.

Bromberg:

By the way of fusion, do you mean their manipulation?

Gould:

Yes.

Bromberg:

It wasn’t even declassified yet.

Gould:

It wasn’t even classified yet. [Laughter]

Bromberg:

What does that mean?

Gould:

No, there was magnetic confinement...

Bromberg:

There was magnetic fusion going on in a classified program that was declassified in ‘58.

Gould:

Yes, right. Well, laser induced...

Appel:

[Inaudible; overlapping voices] …that’s what we only think about.

Gould:

Now, let me contrast what I did in response to that with what happened with Schawlow and Townes. Professor Townes was thinking about doing something, creating an oscillator in the visible part of the spectrum corresponding to the maser, and there were notations in his notebook about that. So he was thinking along those lines that you mentioned. However, he didn’t think of the Fabry-Perot cavity, which was the key to generating the beam. That was thought of by Schawlow sometime in early 1958. And the two of them together were able to come up with the laser as an oscillator.

Appel:

The optical maser.

Gould:

Optical maser, yes.

Bromberg:

When did you start calling it laser, right away?

Gould:

I did.

Appel:

But nobody else did.

Gould:

My notebook number one there is entitled some calculations of the feasibility of a laser, light amplification by stimulating the emission of radiation. And yes, they were moving from the maser to the visible, to the light region, and therefore they called it an optical maser. Not an optically pumped maser, an optical maser. And when they thought of that, they didn’t rush out and change their lives to do something about it. Well, they did do something about it. They were in a position to do something about it, but not for the same reasons that I was doing it. They were interested, I believe, more as another type of device or technique that could be used for optical spectroscopy in scientific work. But Schawlow, when he finished his visiting professorship at Columbia went back to Bell Labs, he kept thinking about it. He didn’t do experimental work, but he kept thinking about it. And he had an influence on people there and elsewhere. As a matter of fact, he had an influence on TRG when he came to talk to us once and said, “The ruby can never work. Its fluorescent is too inefficient,” based on his measurements of fluorescent efficiency at Bell, and thereby stopped work on the ruby as a laser material at TRG instantly.

Appel:

[Inaudible].

Gould:

But he didn’t stop Maiman, who was on the opposite side of the continent.

Appel:

Well, then finish your thought, then.

Gould:

Well, okay. Townes assigned a graduate student to work on it at Columbia. For him it was another student thesis. Although it was an exciting idea, neither of them conceived of it as producing a lot of power or having applications other than possible communications, which was in their patent application as a possible application. Mostly it was an exciting new technique that could be used in scientific work. But for me, I saw it could be used to do things.

Bromberg:

It’s a fascinating difference. Well, now before we started taping, you were talking about how you first came to TRG, how you heard of the firm and so, and I’d like to get a little bit of that on tape, how they came to Columbia.

Gould:

All right. Around the turn of the year, at the end of 1957 I was trying to finish up, trying to write up my thesis. And Kusch kept asking me to do just one more experiment with that apparatus, and all the time the idea of this laser was burning a hole in my head. And I just thought, “I have to get out of here and get some place where I can work on it.” Now if I had been Townes’ student, I could possibly have worked on it at Columbia after all, he assigned a student to work on it at Columbia, and that grew into a whole team of people later. But Professor Kusch was a different sort of person. I knew that he would never allow it to be done, if he had anything to say about it, by me at Columbia before my thesis was ever done. And in fact, he wouldn’t have allowed that to be a project for a PhD thesis because it wasn’t basic research. From him that was applied research.

Bromberg:

Did you, by the way, get a chance to talk with him about it, or you decided not to talk with him about it because his attitude was as you describe it?

Gould:

Well, I didn’t talk to him about the laser, no. But I told him, of course, that I was going to leave when I did leave, but I didn’t really say why. And actually, to his credit, he tried several times during the next several years to get me to come back and finish or write this thing up: “And even if you can’t get back to Columbia, you can submit a thesis. I’ll waive any residency requirements,” there and so on. He tried to get me to do that, as did a lot of other people, but once I got into it at TRG there never was a minute left after that to do that. Although I did say in order to get time off at TRG to work on this thing, which I worked on without pay on my own time, I told Dr. Goldmuntz that I wanted to finish my thesis, and I wanted to take off a day a week or so to do that, while instead I was writing up mainly this whole big thick notebook on the laser. Now in retrospect it was kind of silly, perhaps, but I did do it.

Bromberg:

We should tell the tape that you first were introduced to TRG when they came recruiting to Columbia and that was Goldmuntz and Daly. Is that what you told me?

Gould:

Yes. Lawrence Goldmuntz and Richard T. Daly. Daly had just gotten another contract to build a frequency standard, microwave frequency standard.

Bromberg:

That was also a DOD contract?

Gould:

It might have been. I guess it probably was. I don’t remember that for sure. At any rate, he had one contract to build one kind of frequency standard using a cesium atomic beam. Daly, by the way, he’d done his thesis with atomic beam machines also, but at MIT. It was the only other laboratory in the whole world that was using those beams. So he saw how he could use the hyper-fine frequency transition of cesium as a frequency standard in an atomic beam. Then he later thought of, or somebody thought of an optically pumped rubidium gas cell as a possible basis for a frequency standard, and they got a contract to do that. Well, they didn’t have anybody to run the contract, so they came looking for somebody, and they found me. So I was assigned to work on that.

Bromberg:

Just by yourself, or they gave you a team or...?

Gould:

I had a couple of technicians, too. And I worked on it.

Bromberg:

Was that of any interest to you?

Gould:

Not really, no. But I had learned very quickly the reality was that I had to do something useful there to earn a salary and that if you wanted to work on some kind of project you better go out and find some contract support for that. So that became one of the purposes then. And that notebook served several purposes. It served to describe something that I had with me when I came for purposes of accepting that invention from the patent agreement with TRG. It also became the basis of their proposal for a contract. And it became the basis for a patent application, and here is a copy of the original patent application.

Bromberg:

So we’re talking about notebook number two [Yes.] Where you were working on your laser idea according to your agreement with Daly and Goldmuntz that ideas that you came with would be accepted from the company patent arrangement, that they would own the patents.

Gould:

Right. All right, now at one point you asked me what I was doing during this period of time when the laser project was classified, and yes, I was there supposedly doing something.

Bromberg:

Actually, don’t we want to first talk a little bit about what happened when you finally brought this project out into the open? I mean up until now with TRG you really hadn’t told them what you were working on.

Gould:

Well, as I mentioned, sometime in the summer of ‘58 I was busy working on this notebook, but I was also being pressured by Dr. Goldmuntz to get him these invention descriptions. So I thought I’d probably gotten far enough along with it to reveal it and use it as a disclosure for that purpose, and I did. And he was kind of flabbergasted at the idea of this thing, and various people at TRG read what I had written, and none of them could believe that such a thing was possible, although they...

Bromberg:

He read it to, Goldmuntz; he sat down and read it?

Gould:

Yes. He had a PhD in electrical engineering from Yale. But as I discussed it with them, and some of the people there who took part in these discussions were Benjamin Senitzky, Nicholas Salamin, Daly, and Maurice Newstein. Except for Daly, those were all theoretical people. And they could understand the theory as it was written down there, but they are very, like many theodicies, they’re not very good at imagining what a piece of equipment looks like or materials might be used and so on. But just the idea of being able to generate a beam de novo like that totally coherent was something that boggled their imagination. But finally they came to believe in it enough to get excited about it because of what it could do. As I mentioned, it would have enough power to do things like evaporate materials and all the things that it’s been used for, surgery and military applications. And Goldmuntz especially got excited because he saw he would be able to sell this thing to the Defense Department.

Bromberg:

Were there specific applications they were thinking of at this point? And surgery was there any particular thing you were thinking?

Gould:

No, I didn’t think of surgery, but I did think in general about applications where you wanted to bring to bear on a very tiny volume optical power, which as I could calculate, was going to be more intense than any radiation ever had been before except maybe in the middle of a supernova or something.

Bromberg:

So they were thinking of things like weapons, or is that...?

Gould:

Mm-hmm [yes]. And I don’t know if weapons were mentioned in that proposal, but there were some military applications. Let me glance through this for a second. Let me see if I can get Bill.