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Oral History Transcript — Dr. James Wittke

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Interview with Dr. James Wittke
By Joan Bromberg
September 13, 1983

 
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James Wittke; September 13, 1983

ABSTRACT: Research on masers and lasers at RCA’s Princeton Laboratories, 1955-1961. Work on the Dicke hot-grid cell maser. The 3-level solid -- state maser program. Entrance into laser-work after Theodore Maiman’s announcement of an operating ruby laser. Also prominently mentioned are: Nicolaas Bloembergen, Robert Henry Dicke, Hank Reudrich Gerritsen, Herriott, Ali Javan, Henry Lewis, Theodore Maiman, and Rolf Peter.

Transcript

Wittke:

I thought there was some interesting work going on at RCA. I came out here and decided that this was the place I wanted to work, so I started. I came here in September of ‘55. At that stage, the maser had just recently been invented. The solid state maser had not been invented, just the gas ammonia beam laser. Bob Dicke had some ideas on gas cell lasers that wouldn’t require a beam. One of his inventions, I guess in his notebook, he had an idea for what he called a hot grid cell which was, in # concept, a thermodynamic engine that used ammonia for a laser material. It was a sealed off cell, and it had a temperature gradient across it and some high voltages and so on; and by thermodynamic arguments he could show that this would separate out the ammonia molecules into an active region and an inactive region and you could get continuous amplification without the beam requirements of the Gordon and Townes laser. That was an interesting idea. It looked like it might have broader band width, as an amplifier — as you look back now, the band width would have been pretty appallingly small, but — So RCA was interested in pursuing it. I was interested in pursuing it. They hired me, and the first job they gave me was to try and build the Dicke grid cell laser.

Bromberg:

I see.

Wittke:

I worked on that for a couple of years.

Bromberg:

As a full time project?

Wittke:

It was full time. I was the only person on it, but I was working full time on it, trying to bring the concept into a workable device, and I failed. At best, even if it worked, it would have been marginal as a device, as a useful thing; as a nice graduate school demonstration, it would have made a beautiful thesis for someone. But as a practical oscillator or amplifier, its performance I think would have been marginal. But in any case, I was a neophyte. I wasn’t good enough to get the thing to work. Whether anyone could have is another thing, but it never worked, and while I was still working on it — I worked on it I guess for about a year and a half — at that stage, Bloembergen came out with his announcement of the solid state paramagnetic laser. And it immediately became apparent that for just about anything you wanted to do with a laser, that was a much better way to go than the gas cell thing I was working on.

Bromberg:

He came down here?

Wittke:

No —

Bromberg:

— among other things, did he come down and talk to you?

Wittke:

No. I’ve met just about all these people at one stage or another, but no, he never came down as far as I know that year. Maybe he gave a colloquium three years later, but as far as developing or starting RCA policy, no. He published his results, on the potassium ferrocyanide laser, and that (laser) seemed to us much more promising, offered much greater bandwidth, a better device. At that stage, the Laboratories was still doing a lot of what you might call academic research or basic research, not tying everything they did to a possible product. But one always had the feeling, it was an industrial corporation, and your real payoffs come when you do something that’s useful to the corporation as a corporation. And we were in communication, and microwave low noise amplifiers looked like a very important device, whether for military applications or commercial applications, and so that seemed, to my superiors and to me, that that was a much more feasible thing to do than to work on a gas device which would have very low power, very low gain, might be a stable oscillator. Dicke and I had worked, and others over there, Princeton University, others after me and before me, worked on a frequency standard type of device. Several of Dicke’s thesis students got their or through thesis related frequency standards. My immediate superior was Rolf Peter who was a group head in charge of the microwave group. The big effort in microwaves then was low noise traveling wave tubes. RCA had a very large effort, maybe a dozen people in the microwave group. Eleven of them were working on low noise traveling wave tubes, and I was working on this laser thing. They were all traditional electrical engineers. I was the only physicist, and almost the only physicist in the corporation. There must have been five or six others. That was the era of color television and electrical engineers. The lab was just starting to try to build up a scientific background.

Bromberg:

You weren’t here physically, were you? Where was RCA at that point?

Wittke:

Physically I was here. The labs were built in ‘42. It was the beginning of the war. It was all doing radar and war work and that sort of thing here.

Bromberg:

Was that what built up the microwave tradition that they started during the war?

Wittke:

I think so, yes. I think probably. They were making microwave transmitters. I guess it was largely military. I don’t think it was too much intercontinental microwave link and stuff at that stage. It was mainly military applications of microwaves at the end of the war and so on.

Bromberg:

I guess I, really surprised that RCA let you spend a year and a half on the gas cell laser. I haven’t any particular reason to be surprised. Is it what you said, that your perception that they were really sort of more of a research laboratory? What were your bosses saying to you when you were doing this?

Wittke:

My impression was that they go into the war, working strictly on military communications: radio, radar and so on. Right after the war was the era when Sarnoff pushed color television, and I would imagine for five years before I came, maybe even before then, late forties through the early fifties, the laboratories did, I think, essentially nothing but develop color television. And just before I came here, half a year or something like this, they’d finally gotten the FCC to say the RCA’s suggested compatible television system was the way we were going, and not big wheel’ color television, but the electronic compatible system was going. Everybody had been knocking themselves out day and night on that for years, and I think the feeling was, “All right, now we’ve got color television, got it as a product, the divisions are going out to make it, we have to look around for other things. Science has won the war. All the people we’ve got for past years have been electrical engineers doing circuits on color television circuits and so on. We should broaden the lab’s scope. We should get in physicists, metallurgists, chemists. We should get into materials work. We should start developing semiconductor work. We should try to broaden it out.” I think that was a general trend.

Bromberg:

So if we were to look for management records from that period, we would possibly find people looking at changing directions.

Wittke:

I think so. When I came here, Dr. Irving Wolff was the vice president in charge of the laboratories, in Dr. Webster’s present position, man in charge of laboratories, predominantly an electrical engineer, but he was very broad, interested in all sorts of things. He had something like six or seven laboratory directors reporting to him. One was systems research, which was, I guess, George Brown. He was there either then or later. They were worried about antennas and broadcast equipment and propagation, sort of traditional radio type tying. There was the electronic research laboratory under Ed Herold who was interested in electron tubes and cathodes for electron tubes and the microwaves group was one of the sub—groups in that area. There was a physical and chemistry laboratory which was under Lefty Leverenz and they had chemists and physicists working on magnetic materials, studying magnetic properties, semiconductors. There was a lot of work going on germanium, silicon, germanium-silicon alloys and they were just starting on the III - V’s at that stage. I don’t remember the names of all the other things, but the corporation was trying to be represented in these ways. There was one that was more or less military stuff. I forgot what that was called. But the electronics lab, research laboratory, was, as I say, electron tubes, which was mainly microwave stuff and cathode materials and so on. The physics and chemistry laboratory, which you might say is where I might logically fit in if they were hiring physicists and so on, they had people they hired, in that era, to work on getting the basic properties — very little was known about semiconductors then — the basic properties, Hall effect and band theory. They had Frank Herman, the band theory theorist, who has since moved on to Lock heed and other places, very well known, one of the early people in doing band theory. They had people measuring magnetic properties, ferrites studying theoretical —

Bromberg:

Were you indeed with that group, or were you with the tube group?

Wittke:

I was in the tube group and the microwave group, but in this era, you got to know everybody, and you interacted strongly with everyone. You’d go to their talks and they’d go to your talks, and you knew what everyone was working on. It was quite a bit smaller. I guess there were about 150, 180 staff members, and now there’s, what, 450? About double, triple in size. There were very few of us who knew much about the basic core of the lab, the people who were building color television. They were all electrical engineers, let them go up and do their circuits. Here’s this new group of physicists, chemists, metallurgists who were studying materials and so on, and we interacted strongly with each other, even if we weren’t working in the same area. So I’m not quite sure why they hired. Whether it was Doc Wolff saying, we should get some new physicists in with new ideas. Dicke had worked up at the MIT Radiation Lab and has ties and so on. I don’t know, but I think there was a general flavor of, semiconductors coming along, we’d better have a good solid state physics effort and metallurgy effort and semiconductors, we want to get new ideas for extending the microwave spectrum up to higher and higher frequencies, up to the millimeter waves, and so on.

Bromberg:

Is that connected with the war group, or just in general?

Wittke:

I think just in general. The basic motivation, I don’t know. I think it may well have been military. At that stage, the first, I guess ten or fifteen years I was here, they were saying we had 10 percent or 15 percent of the laboratories work is directly on government contracts, and we want 20 percent of 22 percent. It was on the order of fifth to a sixth, or seventh, something like that. For a while they said they wanted to keep that there. Then, they wanted to build it up; and then it was, well, we really want to build it down because we don’t think military contracts really support the corporation the way we want. It’s too heavy an emphasis, let’s de-emphasize it. But in that era, it was about a quarter to a fifth direct contract support, or work in an area that we could hope to get contracts because we had the knowledge in that area, so it was strongly motivated. This was the era of the Cold War and the atom bomb, Russian bombs and everything else and the hydrogen bomb. At that stage you had to have a security clearance.

Bromberg:

Just to work here?

Wittke:

Anyone who was hired here was immediately cleared for Confidential. If you couldn’t be cleared for Confidential, they wouldn’t hire you. There was Secret work going on as well. I don’t think there was any Top Secret work going on when I came in the mid-fifties, but there were some places in the lab where there would be a desk sitting in the hall outside with a guard sitting there and you couldn’t get in. The door was kept locked. It was an era of military awareness and concern. Everyone had to wear badges and it had your clearance on it and it was Confidential, and I think that was Army clearance. There were separate clearances, and when you worked on Navy projects then you’d get a Navy clearance. I worked on a Navy communications project to communicate with Polaris submarines, and I had to get a Navy Secret clearance. This was when they were building the Stellerator C for controlled fusion and that was still classified very strongly, and my lab director, Ed Herold, took a couple of years off and was assigned to it. The company was making high powered tubes for it, radio tubes to drive the Stellerator, and so he went over there Forrestal Campus of Princeton University to serve as a full time representative of the company, and the company though they might get involved in fusion through high powered tubes or whatever. They wanted some man on the site, and they even cleared a few of us here at the electron devices lab, and we got the atomic A.E.C. Q clearance just in case they wanted to put somebody on that project. I got atomic Q clearance. Never used it. Maybe some FBI man’s following me around now because I had these secrets — I never got access to any secrets or anything else, but I was cleared. So, you had it. It took six months sometimes to get cleared and they had to think ahead and they were clearing people. And gradually, as the years progressed and things quieted down, the badges went away. I don’t know now whether they clear people automatically or whether they do any background check or what. It’s always been a bone of contention with me, let me tell you — when I was looking for a job, one of the places I went to was Bell Labs, and I asked them, I talked to their personnel man and he asked, “Do you have any objection to being cleared, by a security check?” I said, “No, not a bit. But what kind of clearance would you clear me for, Army clearance, Navy clearance?” “Well, no, this is just a sort of company clearance to make sure there’s nothing in your background that might cause us trouble, because even if you aren’t working on classified stuff, there are people who work sometimes at Bell at Murray Hill and sometimes up in Parsippany or Whippany where they have classified stuff; and you might be sharing you room or be across the hall, and it wouldn’t look good if you were near this person with Secret clearance and you weren’t cleared or something.” That irritated me, I must say. It was one reason I didn’t go to Bell — the thought of some sort of ‘private clearance’ that didn’t really clear you for anything but they wanted your authority to snoop behind your back. I said, “What happens if I say, since it doesn’t clear me for anything, I’m not willing to have you investigate me in this private way?” They said, “Well,” they were honest, they said, “we probably wouldn’t hire you.” That was sort of the era of those days. That’s one of the reasons I came here instead of going to Bell Lab.

Bromberg:

Now, when Bloembergen’s discovery came along, do you have any recollection of the process that led people and you to move into this?

Wittke:

I can tell you. I think I can reconstruct practically what happened, although I don’t guarantee it’s indeed what happened, but my immediate boss, kept aware of —

Bromberg:

This is still Herold?

Wittke:

Well, this is Rolf Peter, my group head, who we under Herold. He was aware of things — this made a big splurge when it came out, and he called me in and we discussed this thing, and it was decided that we really should get involved in paramagnetic resonance. And we didn’t have the facilities. At that time, you needed these big Varian magnets, and things, the magnets in the lab were little things that weren’t very homogeneous, and we decided that we should look and see what would be involved if we went into this. I came back and said, “Do we really want to get a big 12 inch Varian magnet? You need such and such X banc microwave equipment and this, that and the other thing, and it would cost so much money.” At that stage, the laboratory’s management had a not very understanding and somewhat tightfisted approach — They said, “Well, look, down in the magnetic group; there’s a 12 inch Varian magnet, can you share that magnet with them or something?” Well, they had no conception that you build equipment in and around it and you couldn’t possibly share something like that. Nobody would get anything done, just doing what had to be done to take it from lab to lab, and you’d waste all your time. It cost $12,000 for a magnet. When I pointed out that you couldn’t possibly share it, they went ahead and bought the magnet. It wasn’t that, but it was the question of “Well, can’t you share?” $12,000 in those days was an awful lot of research money for capital equipment, and they were squeezing every way they could to try to —

Bromberg:

Was that the biggest piece of equipment up to that point?

Wittke:

For this thing, yes, that would be the biggest dollar outlay, buying that. We had the Zurich Laboratory, you’re aware of the Zurich lab?

Bromberg:

I guess I don’t even know what you mean.

Wittke:

When the laboratories were set up here in ‘42, the theory was to take all the advanced development and sort of more “researchy” parts of all the projects and centralize them here for the corporation-wide, and that’s what this was. After, I guess it was in the late forties, after the war certainly, maybe it was early fifties, they decided that it would be desirable to have a satellite laboratory in Europe, where you could keep tabs on what was going on in European circles, recruit European scientists, and so on. So they set up a laboratory in Zurich, which is still going, to do research just as was done here, but try to go to European conferences, tap the European brains, drain them into our area and so on, have interactions. Then later on another one was set up in Tokyo. The one in Tokyo has in the past few years been sold off, and a couple of the Tokyo people transferred here.

Bromberg:

I knew that DOD does that kind of thing, but I didn’t know private corporations did.

Wittke:

Well, for a while there IBM had, I guess they still do, a satellite laboratory in Zurich. I’m not sure whether GE does or not. But RCA was one of the first, certainly the first in Zurich. They set up a laboratory there, and they had people there, and one of the people over there, Hank Keudrick J. Gerritsen, who’s now at Brown University, professor at Brown, came from Holland after the war and worked at the laboratory there. He was very interested in getting involved in laser research and paramagnetic resonance, and he arranged to get transferred over here to join the microwave unit to work on this. I was sort of put in charge because I was the only person.

Bromberg:

He got transferred about ‘56?

Wittke:

About ‘56, ‘57, somewhere in there. I guess it was about ‘57, ‘58, because I’d been working on the gas cell for a couple of years. I came in September of ‘55. And he offered suggestions by mail about the king of equipment we should have and everything else, and we tried to hire somebody else, to get three of us working, and they were able to hire somebody. I think it was either just before Gerritsen came over here or just after, Henry Lewis, who later became my group head and then lab director, and how he’s up at Dennison, vice president or something. So there were going to be the three of us working on microwave lasers, more maser materials and not so much lasers per se. We started out trying to find better materials. They had potassium ferrocyanide, and it had its advantages and so on, but there was not much research in that. At the laboratories we weren’t trying to build operational amplifiers, we were trying to study, do the spectroscopy of materials first. Eventually, the three of us got the equipment together and were working on it, in the microwave group. I think we were still under Rolf Peter then. Leon Nergaard took over as group head some time along the way there. Rolf Peter was made director of the physics and chemistry lab, and Leon Nergaard was made group head of the microwave group. I’m not quite sure of the dates. This would have to be checked back on. And I think we were the first people to report on iron doped rutile. Rutile is a maser material, iron, chromium doped and so on, and we did a lot of work on that. The practical applications were taken over by the Advanced Technology Laboratory, a sort of advanced development laboratory in Camden — military government assistance, whatever it was called then, it’s still going quite strongly — and they were developing actual working amplifiers, low noise amplifiers using our material. We still stayed on with spectroscopy and materials and so on.

Bromberg:

Is there anything interesting in the way of memoranda between you and this Camden lab that we should keep in mind?

Wittke:

The turnover of personnel there has been fierce. There’s still, one guy down there who, I think, was in on it at the beginning, Charlie Reno. Most of the people down there moved on to different things. Several years later one of the group heads down there was Jim Volmer who is now vice president somewhere up here in the glorified strata of the corporation. He was a group head in charge of the physics part of ATL when they were still actively working on microwave masers, on various contracts for radio Astronomy or military use or something — but that was several years later.

Bromberg:

Just to pause a little bit and think about documentation — well, of course, you had laboratory notebooks, I assume.

Wittke:

There’s laboratory notebooks on the spectroscopy.

Bromberg:

Were there internal reports, aside from those that got published?

Wittke:

Yes. Well, any time you publish something, you had to first issue it as an internal report. That was a company policy. I think it still is; I don’t know. So that for everything published there is an internal report, but there are certainly internal reports that are not published, and in half an hour I could go through the file, knowing the names of the people — they have a card index of all the internal reports by the author’s names — and I know the authors who are apt to publish in that area, and I could just go through all the things they published and pick out, or anyone else could, for that matter.

Bromberg:

Where are they physically, these internal reports?

Wittke:

In the basement. The library keeps those. The library is responsible for maintaining an archive of them. They’ve kept them. They keep the file by index card, by title of the thing and by author.

Bromberg:

Do you have stuff in your personal files that would throw light on these researches.

Wittke:

— only my own stuff. I have lab notebooks. I haven’t looked at them in 20 years.

Bromberg:

Sometimes correspondence is particularly —

Wittke:

People were invited to go out and give papers at various meetings and so on and I gave several of those, and wrote articles and so on, but this is all open literature sort of stuff. On some of the papers I wrote — I gave one at the National Electronics Conference or something years later on low noise microwave amplifiers and parametric amplifiers as well as masers and so on that was never published. I don’t think it appears in the Proceedings of their thing. But that would probably be an integral report that would be around, something like this. But the documentation, the way things were set up didn’t really generate documentation. People in Camden would set up a program. They’d go out and get some government contract to build a microwave maser. They’d come up here. They’d talk to us. They had problems, sometimes we’d go down there, we’d discuss it, but it was all on the phone or running back and forth. There was very little written thing. Certainly no historical documentation to try and document things as you went along. I would say, from when I first came in ‘55 until the mid-sixties or about 1970, the people I mainly associated with were the more scientific, academic type of people, and the basic motivation for most of us was getting a name, reputation in the area, and publication. You get the name through publication and giving papers and so on. You’d work on something and you’d write it up, in an internal report, and ask permission to publish it and publish it as a paper. And that’s the only documentation really apart from the notes along the way, in your notebook or something, taking of data and so on, would be the final publication; and generally when you’d published something, you’d take all your notes and throw them out, because you can’t accumulate 16 years of debris — it takes a lot of filing space. So the company has a strong policy about anything that might be patentable should go into a laboratory notebook and so on, and they encourage everything to go in the laboratory notebook because they say, who knows what’s going to be patentable and prove priorities or anything else. And in patenting, you can show in your notebook, if it’s witnessed, that you were working on this before somebody else did something, and therefore you couldn’t have copied from them. So they have a strong thing. So laboratory notebooks were the prime sort of internal documentation, apart from these integral finished reports that never got published.

Bromberg:

OK. If you, you know, happen to think of something, piece of historic equipment that you just decided to save, or anything of that sort, or a paper that you never published but you happen to keep.

Wittke:

Well, the first laser that we made, for example, after Maiman showed that you could take a GE flash lamp and stick in a ruby rod or something… Roscoe Williams was the fellow who was here then, he is no longer with us, I think probably he may have gone on his own. I wanted to build a laser, but the first thing that I know is, he’s ordered the capacitors and the power supply to charge up the capacitors, and built a little cabinet and he’s bought a few flash lamps and wired it up and bought a ruby rod and had it silvered and mounted it up, essentially copying what Maiman did, and I remember the thrill of his inviting people down to this little room, and he turned out all the lights and everybody would look at the wall, and “Four, three, two, one, Pow,” there’d be a large band, as the capacitor bank discharged and a little bright red spot would appear on the wall. Everyone would clap like mad. We’d bring in lab directors and vice presidents to see it, and it was great excitement. Then, for six months or a year or something, we still were doing flash lamp excited laser work and somebody would take away the power supply to use it and the laser itself and its flash lamp reflective thing would get stuck out in the storage room, and then after 20 years someone would say, “Gee, this has no real application.” For all I know, the thing may be out in the storage yet, but they’ve had periodic cleanups out there. You can’t store everything. They give equipment away to universities and schools and such. “Here we’ve got this old ruby laser power supply that we aren’t doing work with any more, it’s got all these big capacitors, it would cost you $500 to buy the capacitors and power supply, can’t you use it?” “Yes, we can!” We give it to somebody. I guess we took a tax break or something. We unloaded all our material things, just to get the storage space, when we weren’t interested; we generally gave them away if they were of any use, or even junked them. There wasn’t much stuff saved.

Bromberg:

At some point you were working on some of Dicke’s ideas on infrared lasers, altogether, so that the Maiman discovery must have intersected with some laser work here. Now I know that Dicke had these disclosures that actually were patented.

Wittke:

As far as the infrared goes, we never did any experimental work on infrared lasers or masers or irasers, whatever you want to call them — as it was referred to when the term laser was coming along. I though laser was a terrible term. I never used iraser or uraser.

Bromberg:

You thought laser was a bad term?

Wittke:

I though laser was appalling. I liked molecular amplifier.

Bromberg:

I see. That makes sense.

Wittke:

But it wasn’t always molecular.

Wittke:

Different transitions in ammonia would get you up in the infrared vibration or possibly rotational transitions, and his (Dicke’s) ideas, as I recall, were all beam type devices, and the technology for detecting these very short waves and everything was very primitive then. It just looked like experimentally a very difficult thing to show, that if it worked, it was working, and it wasn’t clear that it would have any use because the atmosphere probably wouldn’t be transparent so you couldn’t use it for communications, and it looked like it would be only one or two wavelengths so you couldn’t really use it for spectroscopy. You could do some very nice physics of the ammonia molecule but it was an academic type of thing rather than a practical one.

Bromberg:

I didn’t realize that. I had picked up somehow the idea that there was a program.

Wittke:

No, only the hot-grid cell which was in the microwaves, one and a quarter centimeters. We had not actively started on it — we were aware of it, Dicke was a consultant then, patents were assigned to RCA and so on, but we didn’t do any experimental work on the infrared stuff at all, on these ideas.

Bromberg:

You were doing strictly masers until Maiman.

Wittke:

Until Maiman came out of the blue, yes. At that stage, because the microwave group when I first came here was working on traveling wave tubes and had a very strong effort on low noise — Bell Labs also had a very strong effort on traveling wave tubes with low noise — and there was a great deal of exchange of ideas, and it was competition, but it was quite equal. RCA was doing as much as as Bell. I was amazed — I don’t know anything about anti-trust, but I was amazed at the amount of exchange of information. We’d go up there and they’d show us practically everything. They’d come down and we’d show them everything. It wasn’t trying to keep our secrets from them. It wasn’t that we were collaborating in any way, but we weren’t trying to say, “This is proprietary, don’t let them anywhere near,” and people in microwaves were generally the ones who got into maser work, or laser work, at Bell. And Ali Javan I knew — you got to know all of these people — he was at Columbia and some of the people from Columbia were here. I knew Townes. I worked with Dicke on my thesis and everything and — you knew everybody, and I remember going up on a microwave traveling wave tube visit sort of thing when Javan and Bennett and Herriott were working on the gas helium-neon laser, and they were very close-mouthed about what they were doing. They showed us some of their very nice spectroscopy, but I was too stupid to envision what a laser might look like from what they were showing us. It was all just decay curves of excited states and so on. A beautiful piece of work. They were working on that, I would gather, for, my guess is a year or so before Maiman came along, but they hadn’t got it working.

Bromberg:

…He was working on that since about ‘59, I believe.

Wittke:

Yes. But they were working on gas lasers on solid state lasers.

Bromberg:

So I should think about RCA principally doing the traveling wave masers?

Wittke:

What I’m saying is, when I came, it was traveling wave electron tubes. That’s what Bell’s microwave group was on, and that’s what we were on. I was the only one coming in as sort of the atomic quantum electronics area. I was hired to sort of start that effort here.

Bromberg:

I was assuming that when you got into the solid state masers, you did traveling wave masers —

Wittke:

OK, yes, I’m sorry. At the laboratories, we — (crosstalk)

Bromberg:

We’ve got you in the solid state with Lewis and Gerritsen.

Wittke:

— OK, the three of us were doing spectroscopy of materials, just observing transitions and everything else. About that stage, I got transferred over to this classified Navy project, talk to submarines. Lewis and Gerritsen went on doing this resonance and so on. They built maser amplifiers, but they were all cavity amplifiers, no traveling wave beams, a resonant cavity with a whole piece of the material in there and a pump frequency. Then there were several papers published in that area, you’ll find, by them and Ed Sabitzy who was hired about that stage, and he was also working on masers. Lewis got off on other things too, I think, or maybe he was made group head, I don’t know, but Gerritsen and Sabitzy did an awful lot there together and Lewis and Gerritsen did an awful lot together on masers, amplifiers, but they were all cavity work. All the traveling wave maser work was done in Camden and ATL (Advanced Technology Laboratory). And of course people, as I say, went back and forth and communicated, but no traveling wave maser work was done here, developing devices. That was all done down there, in engineering. The principles were who in cavity devices here. And then along came the laser, and when the laser was announced, I was doing some optics experiments, because at that stage I had become convinced that optics was going to become important in communications, probably for the wrong reasons.

Bromberg:

How come?

Wittke:

Just, I guess, without really understanding the situation very well, I had the feeling the band widths were obviously infinitely greater — you know, just a logical extension: you extend up to microwave. If you try publishing into the very short microwaves, you get into attenuation problems in the atmospheres, technical problems and everything else. But then if you went on farther, you could modulate light, and the transmission opens up again, and the band width is huge, and so on. And I didn’t really understand all the subtleties of coherence and incoherence and everything else. There was one fellow here who has at that stage, that was N — *. When we had the microwave group, there was a couple of people doing optics. There was one fellow, German fellow, — a lot of microwave people came over from Austria or Germany or something after the war and took jobs here, I guess for better jobs, — with very good microwave background, — this guy came here, and he was working on an optical amplifier of a funny sort. All it was was a very bright arc lamp, and it went through essentially a triode, an optical modulator, to a detector, and he hoped to put a small amount of power into the modulator, and modulate a large amount of optical power, and use that for transmission, so you could send signals. With a small amount of power you could modulate a large amount, of incoherent power.

Bromberg:

Right.

Wittke:

And he built equipment about the size of that little there. I don’t remember what it looks like, I don’t think it’s still around, but it was all strictly incoherent light.

Bromberg:

When was this, about?

Wittke:

It was before the laser was invented, so it must have been about ‘59.

Bromberg:

— because of course there was a lot going on then, Townes’ and Schawlow’s paper —

Wittke:

The paper had come out, and it made a bit stir, but nobody quite knew how to implement it.

Bromberg:

You tried?

Wittke:

We didn’t try anything here. Nothing was done. We were all strictly microwave maser, as far as coherent sources goes, until after Maiman had demonstrated his. Then as I say, Roscoe Williams built a ruby laser, and not much more was done, we did a few preliminary things like trying to burn through razor blades and so on to show the power, more of a demonstration. I think the gas laser had been announced by Bell before we started on our real laser program, but at one stage along the way, Dr. Webster who is now vice president in charge of the labs was then laboratory director of the electronics research lab or something like this, and he set up a group under Henry Lewis. Henry Lewis was a staff member, as I was, in the microwave group. He formed a new group with Henry Lewis as group head, to work on lasers, and we brought in various people. He hired Foltan Kiss whose name may have appeared to you, from Toronto, he just came out of school, and they set up a group to do work, and that’s when a large amount of solid state laser material work started, trying to find new crystalline lasers other than ruby that might be more advantageous. And we were working on a many-year program, five to ten people working on it continuously on various aspects of spectroscopy, amplifiers and so on, on crystal lasers. Somewhere along in this period, Johnson at Bell came out with the neodymium-YAG laser which has sort of taken dominance since then, but we went on before them and after them, looking at a variety of things, double doping and so on. Bob Pressley, who was here and has since worked at various places and now has his own laser company, was here at that stage. A lot of people were involved in this, and that is an era that, if you’re interested, I can supply, I think, information as to RCA’s involvement as well as anyone.