Oral History Transcript — Dr. Lee Cross
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Lee Cross; May 10, 1984
ABSTRACT: Founding of Trion Instruments. First commercial lasers; pricing, markets. R & D contracts with Department of Defense Agencies. Trionís collaboration with Jarrell Ash on a laser microscope. Lear-Siegler acquires Trion.
Bromberg: Iím with Dr. Lee A. Cross at the University of Dayton and weíre going to talk a little bit about Trion Instruments.
Bromberg: You were a graduate student at the University of Michigan. Why donít you begin by saying a little bit about what you were doing there that is or were not relevant to Trionís work, just to get an idea of what your background was?
Cross: Actually Iíd returned from a two year stint in the Army.
Bromberg: That would be, what, 1960?
Cross: That was, letís see I was drafted iní58 that would have been the academic year Ď59 -Ď60. I got out of the Army early to go back to school. About the end of that academic year, this was post-Masterís degree classwork that I was doing plus research work which was totally unrelated to lasers —
Bromberg: — that was in physics?
Cross: Yes, it was in physics, and Lloyd Cross had the idea of manufacturing maser amplifiers for special purpose applications, and we formed a partnership and sold two maser amplifiers to a buyer who, I donít know, I canít remember who it was, but that was the basis on which we got the first financing for forming Trion.
Bromberg: Tell me, when you did this, did you do it out of your garage, or where?
Cross: — yes, essentially. Essentially it was done out of the garage. We subcontracted some machine, and we ran around buying various parts that were necessary to assemble the thing. As I recall, the masers were based on iron-doped sapphire, but this is all extremely vague in my recollection. And we managed that way to raise $1500 from the sale of those devices.
Youíll find that our financial history is extremely interesting!
Bromberg: I do want to know what you were doing that made him get you to do this.
Cross: Well, you see, as an employee for the University of Michigan, I think he was prohibited from having outside business interests, so he had to get up whatís called a front, somebody to act as his agent, to officially do the selling.
Then, about that time, Maiman made his announcement of laser action.
Bromberg: That was already about June or July in Ď60.
Cross: Yes. And Lloyd constructed his own system with a [???] and I believe he built it himself completely from scratch, doing all the polishing of the ruby and everything. But I was disconnected from that. I didnít know what was going on.
But he then suggested that we continue on with this, now officially form of honest-to-goodness corporation, and abandon maser sales because they would never amount to anything, and to form a corporation dedicated to the manufacture of ruby lasers.
Bromberg: And you were right in the middle of graduate work?
Cross: Well, I quit graduate school, because frankly you canít support a wife and two babies on a graduate studentís salary. So —
Bromberg: — with whom were you working here?
Cross: Right here?
Bromberg: No, whose student were you?
Cross: I was not formally a doctoral candidate at that stage, so I was working for a man named Sam Krimm. I believe heís still at the University of Michigan. He did X-ray diffraction studies, and we had a — thatís the basic area of interest that I was working in at that stage. I was doing [???] studies.
So, letís get back. So we made this decision, to form the company, and the three primary founders were Lloyd Cross, me, and Douglas Linn. We financed the formation of the corporation out of the original money that we got from selling the masers.
Cross: Well, it didnít cost much to form a corporation. Even nowadays, it only costs $550. Thatís $400 for the lawyer and $150 for the corporation fee. It costs nothing to form one. But what that does is, that gives you the ability to raise money by selling stock, which we proceeded to do by approaching friends and relatives. And the original money on which Trion Instruments was based was $30,000.
That allowed us to set up a manufacturing facility, to hire a couple of people who were dedicated to the production side. One of them was named Dennis Mahallic. The other one was named Jim [???], youíll have to find out what Jimís name was from Doug Linn, for example, because they were good friends. Those two people were essentially picked up from their factory. I believe they were both employed by GM in Flint, Michigan. They traveled down to Ann Arbor and formed the nucleus of the production part of the company.
Bromberg: They were technicians at GM?
Cross: Well, Iím not exactly sure. Dennis turned out to be a real driver in terms of getting people to produce, so he eventually turned out to be in charge of production of laser units.
The first ones we sold were complete systems that cost $5000 apiece, and I believe we sold the third commercial laser made in the country. There were two made by some company, Iím not certain who it was. They sold for $25,000 apiece. Ours cut the price to 20 percent from what the going rate was.
Bromberg: When you say complete system, you mean the mirror, the —
Cross: — yes, the complete laser head, power supply, capacitor bank, trigger system, everything. And that was a reasonable price to charge for one, too, at that stage, because youíre talking about 1961, Ď62.
Bromberg: That sounds like an awful disparity. Itís curious to me that the field was so unsettled that people could charge anywhere from $5000 to $25,000
Cross: Thatís because youíre not familiar with the difference in costs between a commercial company and a research institute or organization devoted to research. Right now, for, that is up to April 15 of this year, I worked for the Research Institute of University of Dayton. I no longer do so. I now head my own company. But the reasons that were meeting here is because we made arrangements, I made arrangements with you earlier to meet here and gave you directions how to get here. Iím on very good terms with the people here, so thatís why weíre doing it here.
Anyhow, unless you have actually gone through the process of budgeting something for a research institute, versus the way that itís done in a commercial company, you wonít understand why thereís that large disparity. Plus the fact, we think that those first people charged a whole lot of money more than what should have been charged.
Bromberg: That was TRG or what was the first?
Cross: I donít remember. It might have been TRG. No, it wasnít Hughes. It might have been TRG. It might have been TRW. Iím not sure.
Bromberg: I didnít know they were in it so early.
Cross: I donít know. Perhaps somebody else would know who it was.
Bromberg: So you worked out what you thought commercially the price should be in terms of what you were —
Cross: — thatís right, what it cost us to build it.
Bromberg: — was there a lot of development of just science necessary to get this product, this laser ready?
Cross: No. Very, very little, as a matter of fact. There was mainly engineering, and a lot of it was simply identifying suppliers. One of the problems that we had at the very beginning was the difficulty of getting the flash tubes, 4000 capacity flash tubes, — as I recall, there were two possible suppliers. One of them was General Electric and another was a company called Kemlite in Chicago, and we were very thankful for Kemlite because they produced the lamps for us, and I believe, up until the very end of Trion or the company that Trion evolved into, Kemlite was the supplier for the lamps. I could be wrong but I believe that is the truth.
Bromberg: Those are just xenon flash lamps?
Cross: Yes, xenon flash lamps, but you see, lamps that will take 4000 Us are not made by everybody, and to the best of my recollection, we never changed the lamps. We always used them.
Bromberg: So here you were with your $5000 laser. Now, is this — you mentioned í60?
Cross: No, this must be Ď61. Late Ď60, Ď61, to the best of my recollection. And we, these things, these were long pulse ruby lasers, nothing fancy, at that stage nobody knew anything about Q switching, and we sold a variety of them, a number of them, I should say. I am very vague on the business details, because my job had nothing to do with sales.
Bromberg: What were you mostly responsible for?
Cross: I really canít remember what I was doing! I try to think, let me think of all the neat things I was doing early on, and the answer to that question is, I canít remember very many of them.
Bromberg: 20 years is a long time.
Cross: Yes, 20 years is a long time, but, in essence, the details of sales youíll have to find out from somebody else.
And we ran out of our $30,000, as you might imagine, and we were very fortunate to find another stockholder. This was now a real investor, at least according to the scale we were on. We found an investor whom I canít identify who bought some stock, and his cash contribution was 100 K. So that got us off the ground. That let us run for a while, before we ran out of that money. We made a big mistake, as many small companies do, if expanding too rapidly, expanding a lot more rapidly than our sales expanded. We projected sales which didnít materialize.
Bromberg: Now, do you have any recollection of where you were expecting sales to be at this point?
Cross: Well, weíd had a fair amount of success selling to various laboratories; various individual scientific investigators who just wanted to have a ruby laser.
Bromberg: Right. The Franken group for example?
Cross: We never sold one to Franken but I think we either sold or rented him a head. He had a Trion head, but he had his own power supply and capacitor bank.
Bromberg: I see, because he does mention Trion when heís talking in his paper on nonlinear optics.
Cross: Thatís right. He had the power supply and the capacitor bank, and he either borrowed or bought just the laser head.
Well, again, Iím going to have to be vague on this because I donít know who we sold lasers to but my general impression is that they were sold to government laboratories like Ray Patterson Air Force Base.
Bromberg: Art Guenther, I guess.
Cross: Yes, Art Guenther in New Mexico. One was sold here. They tried an instrument laser here. In fact, when we first built them, OK, they were built in individual modular cabinets and then bolted together, and thatís the variety thatís here at the University of Dayton. I saw it some place.
Bromberg: Did they use it?
Cross: I donít know. I didnít bother to check. It looked, it was in the lab, and it was being operated, so it looked like it was running. It might be in storage now. I saw one at Ohio State University, one of the old ones, in a modular cabinet, so I suppose somebody there bought one, but who else might have bought those early ones, I really donít know.
Bromberg: If itís in storage it might be nice to get hold of it and save it, because itís one of the very early commercial lasers.
Cross: Yes. I know thereís one at Ohio State too. But I can check into that if you want me to.
Bromberg: Yes, Iíd like to know about that.
Cross: But I really canít directly answer your question. The mistake I know we made is, we invested too much money in parts and components, built laser systems that sat there, and werenít ordered, didnít sell. Thatís what eventually forced us to sell out to [???]. It was the imminent possibility of going bankrupt.
Bromberg: Going back, looking at my questions, am I correct to gather that before you started to work with Lloyd Cross, you really werenít paying attention to Stuff like the Schawlow-Townes paper or laser research?
Cross: No. No. I was in an entirely other field. Lloyd might have been aware of it, but I wasnít.
Bromberg: Now, at this point youíve got the Maiman type ruby laser, but youíre getting other things coming out. Some lasers come out of IBM, I forget the material but itís another solid laser.
Cross: Yes, they did a lot of work on tung states, Calcium tung states, barium tung states and so on. To the best of my knowledge, we did not provide any of those lasers, or build them for anybody.
Bromberg: When Q switching begins to be developed, and Hellworth talks about that in I guess the March í61 Berkeley meeting, in post electronics, was that something that you began to work with?
Cross: — was that a spinning prism system?
Bromberg: Are you talking about Kerr cells? I think? At that early stage? Thatís my memory. Maybe you talked about rotating —
Cross: OK, we did not do anything with Kerr cells. A Kerr cell switch laser is not very practical device, although the work is not commercially useful, but the development of the Pockel cell has completely made Kerr cells obsolete. As far as Iím concerned.
Now, the first Q switch system that Trion produced was a rotating mirror device, and it had, it was configured to operate where we had a very rapidly spinning prism, mirror; the operator pushed the button, and the mirror control took over. When the mirror was in the appropriate position, it fired flash lamps and then Q switching occurred when a mirror came into position.
This was called an OPTUL, it stood for Optical Pulse Transmitter Using Laser. And it fit on the front of our slender laser head. In other words, it replaced the front mirror.
I donít know how many of those units we sold, but there were an appreciable number of them.
Bromberg: Is that something you were involved in getting?
Cross: No, about that stage, I think it was DARPA, at that time it might have been called ARPA — came up with a project that had to do with the super laser system that was being locked on rockets, and they funded three companies of which we were one, to do a study on that concept.
Bromberg: How much was that contract, in comparison with the kind of money you had been getting in?
Cross: To tell you the truth I havenít the slightest idea. Financing is not my strong point.
So we addressed the problem of whether it was possible to build a ruby laser system that was big enough to knock down an incoming rocket, and of course eventually it got abandoned because it cost several Gross National Products for each laser system.
One of the things that we came up with, which eventually turned out to be very interesting, we came up with the fact that one needed a, I forget what we called it, now they call them saturable absorbers but we called it something else, which was an optical element that would be opaque at low radiation levels, and transmit at high radiation levels. I canít remember what we called it, sorry. But you needed this element; youíd either have to do it electrically with Pockel cells or Faraday rotators, or Kerr cells, this is what they do with the large lasers now, theyíre constructed for the laser fusion program, for example. You have to have an element which will isolate the different stages of amplification of the laser. Otherwise, you lose most of your radiation in stimulated spontaneous emission. That is, just the pass of a randomly emitted photon down the amplifier chain, — another way of saying it is, and your super radiant losses are incredibly high. All right, so what you need to do is take your large laser and divide it into a bunch of smell sections, and then in between these sections, you put in this magical element, which sits there and is opaque until a laser pulse comes through the chain, and when a laser pulse comes through, it passes through that element, saturates it, a small amount of energy is taken out of the pulse to saturate it and the rest of it gets through. Whereas if all youíre looking at is spontaneous emission, spontaneous emission has no chance of getting through.
So we came up with that concept. We were just sitting around talking, and decided that thatís what we had to have, if you were going to have this big monster laser.
Bromberg: Who is ďweĒ at this point?
Cross: I think it was Lloyd and myself. At that stage, weíd started to acquire a number of other people. Exactly at which stage they were acquired or hired, I canít give an exact sequence, but to the best of my knowledge, I was mainly the person who worked on that program. I was the man who eventually wrote the final report. I know that.
Bromberg: This really means that you began as a commercial firm but you soon became a firm that also did government R and D, in a sense, and that sounds as if you added on —
Cross: Well, you had to do some R and D to build the lasers. There was several, there was one green laser I believe built for the Navy, that involved an awful lot of R and D, because there was one large, one 1.5 meter laser built for somebody, and that eventually incorporated our saturable absorbers in the amplifier chain, because you couldnít build that laser without it.
I think, as a matter of fact, it was one of the ones that used the flat ruby laser disks, which set up (booster?) angle, and they were isolated by means of saturable filters for the ruby that we found.
Bromberg: Now, am I getting the right impression when I get the impression that this was very heavily your area, R and D, to get the product.
Cross: Yes, thatís right, because I didnít have anything to do with the sales or engineering, and I did what I could to, mainly to help do the investigations of the scientific part, in order to get new products.
Bromberg: And you worked with Lloyd Cross primarily on this or with technicians?
Cross: At the beginning, because we were so small, it was mainly with Lloyd. As we began to get bigger and get more things to worry about, I practically never saw Lloyd.
Bromberg: He went into the business end of it?
Cross: Yes. And although he did continually inject ideas into the business of a scientific nature, his — our interaction became small, relatively small, — thatís late, before the company fell apart.
Bromberg: And what about Linn, what was his role?
Cross: Primarily, exclusively, business. He handled all the communications. We eventually acquired an accountant. But Doug is not a scientific person. His area was exclusively business.
Bromberg: Actually, we ought to focus a little bit on what the R and D is like, because this is one of the issues that I think is really interesting, what the research and development facilities and activities are in a small struggling firm of this sort, because you know you hear people say, ďWell, the big companies can afford R and D, ď and the general outlook I sometimes read is that R and D is a function of being like the Bell system or General Electric.
Cross: Thatís complete nonsense. At the very beginning we did a lot of really neat things. We may not have gotten credit for them, but we did a lot of really neat things on an absolute shoestring.
Now, the idea of somebody else — you know, somebody else had to be paying the bills, OK. But in general it doesnít take a whole lot of money to test an idea. To prove feasibility is relatively cheap, unless of course itís something like a laser fusion project. But just testing the feasibility for example of a saturable filter turned out to be relatively, it turns out that practically everything acts as a saturable filter for a ruby laser if you get it in the right concentration. People use coffee, for example, to Q switch their laser. Itís always very difficult to find the first one, OK, and now itís —
Bromberg: A cell full of coffee?
Cross: Yes, a cell full of coffee will do it. Not very well, but it works.
Anyhow, getting back to that Q switching business, what we had — OK, so we had the idea of this Q switch, now letís go out and find one. So we looked and looked and looked and we — I had at that time a woman technician working for me, and we tried all kinds of glasses. Unfortunately we didnít try the cadmium sulfite glasses which will Q switch. And we went through all kinds of, all perturbations and combinations, and itís not easy incidentally to find a dye that absorbs rubies. There you need someone like Eastman Kodak; with a variety of chemicals available to them they can do it. We couldnít do it.
What happened, very early on in the business — of course, everybody wants to get rid of ruby wants to find a magical green laser —
Bromberg: That was for the Navy or what?
Cross: That was just because photographic films are not very sensitive to the ruby wavelength. And green is much nicer to work with. So even from the very beginning, everybodyís looking for the magical green laser. Nobody has ever found it.
Bromberg: The argon doesnít do it?
Cross: Well, Iím sorry, solid state. Thereís no solid state green laser.
Cross: Like everybody else, we looked at uranium built glass, beautiful, incredible fluorescence material that ought to lase. Thereís some very fundamental reasons why it doesnít, and those would be more of the things I found out when I did my doctoral thesis, is why uranium glass doesnít lase, but it doesnít lase and it never will. What we have done, however, we had contacted Battelle to grow us some uranium glass, not realizing that we could buy it by the ton from glass companies, so they grew us up just a little piece of incredible junk. I mean , it was absolutely awful, we paid them $2000 and it was a complete mess, but we had this little piece of glass, and we were, frankly we were searching for a Q switch for the neodymium laser, not for ruby, and so this — so Lloyd said, ďWell, cope it, optically cope it, itís got to have some, weíve got to be able to find something that absorbs neodymium laser radiation, either from the ground state or from the excited state, so put that stuff in there and try it.Ē
We put it in there and it worked.
Bromberg: When you excited it.
Cross: When we excited it. And we told all kinds of people about this and all sorts of things.
Then we got smart and we went out and bought a whole bunch of shop uranium builder glass, and we found out, it didnít work but it worked beautifully for ruby. It didnít work for neodymiumÖ had gotten thrown away, so we donít know what happened. We donít know what caused, thereís no way of retracing or finding that magical glass that Q switches neodymium. But uranium glass Q switches ruby. And that was our, that was one of the things we did for practically a shoestring.
Bromberg: I donít know if you were in charge of this, but these ruby and neodymium, were they being patented at Hughes or at American Optical? I mean, did you have to get license rights for this kind of experiment?
Cross: No, nothing like that. Nobody ever sued us. We were too small peanuts. I mean, we were big as far as the number of lasers that were being produced, but our sales were just very small. And frankly I donít know about the business end. I mean, I think Battelle held the Townes patent and they wanted us to buy a license from them. Iím not sure we ever did. But if youíre small peanuts, itís just not worth it for a big company to sue you. So as far as I know, patents were not just —
A lot, also, of course, a lot of the work, this particular work was done for the government, and so, you know, if thereís any tie-in between the government and somebody who has patented something, the government has a relatively free license, can grant it to any of its contractors, and so as far as the government side of it is concerned, weíre completely free to do anything we please, and as far as the commercial side is concerned, I donít know exactly how they avoided paying rights but they didnít, as far as I know.
Cross: Were you patenting your own new things, like this way of separating out the stages of the big laser?
Cross: No, I donít think so. No, we never bothered with any of that. If weíd bothered to try to patent everything we thought of, thatís all we would have been doing is writing patent disclosures. And also, you have to recognize, when the company first started out in fact the first few years that it ran, there was nobody in that company who was older than 27 years old. Nobody had ever had any business experience of any kind whatsoever, and we were not really concerned with trying to capitalize on ideas and applying for patents on them. We had no direction by anybody who had any business orientation. And it was all a lot of fun, and we were having a good time doing what we wanted to do, and there was no reason to patent any of it.
So we wrote a paper describing a glass Q switch, and submitted it, unfortunately, to PHYSICAL REVIEW, and if you look through the PHYSICAL REVIEW to find out how many papers theyíve ever published on lasers, youíll find them extremely limited. And a reviewer of this paper took his good time, very slowly, returned it, rejected.
In the meantime what happened in the interim was that the French people who discovered the use of cadmium sulfide built glasses got their paper published, so theirs was the first one on a [stacked? stag? static?] a Q switch for the ruby laser.
Eventually we did publish the stuff on the uranium built glass.
Bromberg: You really just chose the wrong publication.
Cross: Right, we chose the wrong publication.
Bromberg: I mean, if youíd tried JOURNAL OF THE OPTICAL SOCIETY, you would have —
Cross: — or APPLIED PHYSICS LETTERS, or something like that, it would have come out very much faster.
I didnít realize at the time that that was a bad choice. I just thought PHYSICAL REVIEW was the best, I thought — the thing is, it is not, the mathematical foundations on which you predict the way that the saturable filter ought to work are very interesting. You have to postulate that certain kinds of mechanisms are occurring in the material, but if not, it is really not very physically sophisticated. A very simple model, very simple rate equations, and you can, for this DARPA report I went through derivations, how you figure out how the laser is going to operate and so on, what you need in terms of the absorption cross-section of material and so on.
One of the things that make them work is the absorption cross-section; the emission cross-section for chromium is low. Itís something on the order of 1.6 — Iím sorry, I donít know, but itís a very low cross-section. What it means is, you can store an awful lot of energy in a piece of ruby and the gain will remain low.
On the other hand, in a filter what you want is something that has a very high absorption cross-section, so then itís; absorption is very high, and therefore the combination of the two is low gain from the ruby, high loss from the filter, so when it starts to oscillate, the filter will saturate very quickly, because there arenít very many atoms or molecules in the filter, and all of the majority of the energy thatís stored in the ruby can then be dumped out.
But outside of analyzing that kind of a system, itís not mathematically sophisticated.
Bromberg: So therefore you thought you didnít have enough new physics in it?
Cross: Right. Thatís essentially what they said.
Bromberg: That really speaks to a bunch of people who are not yet sophisticated in the apparatus of physics, to know where —
Cross: — right, thatís exactly right. I think at that stage I might be in that. I was still very young. Maybe 26. And I was not in graduate school yet so I just made a bad choice.
Bromberg: Iím curious also about what the work week was like, what the mood was like a little bit in some of the laser companies around this time.
Cross: Ours was seven days a week, 12 hours a day. For the principal people. I mean, itís like having your own small business. I now have my own small business. I work seven days a week, 12 hours a day, and thatís the way Trion was, for the principal people. I mean, you seldom had time off. We worked Saturdays and Sundays, and frequently into the nights, and sometimes 24 hours straight.
Bromberg: What was the mood like? What was the spirit like?
Cross: I think it was very good. My spirits were very high. The people who were hired to produce the system, of course, for them that was a job. They worked eight hours a day.
Bromberg: And it was the new things you were —
Cross: — developing —
Bromberg: — developing the new — well, I put in this question about your professional universe, of journals and meetings and societies and so on, number 9, did you have time to have a professional universe?
Cross: No, very limited. My professional universe was very very small. It was limited almost exclusively to the company. In fact, I donít think I read any journals, or very few. I didnít belong to any societies. I think we presented papers at only, I can only remember one place and that happened to be the Cincinnati section of the IEEE where we came down and talked about saturable filters and Q switch lasers, a subject that was entirely foreign to everybody at the time, and I came across an old resume of mine, and I believe that was April l964, and that means — I should have brought the resume along. Itís the only resume Iíve got that goes back that far.
Bromberg: So the engineers were well into things at that point.
Cross: Well into some things, not well into everything, no. Maybe I was wrong about this date. Iím not sure. I tell you the truth; I canít remember when the first saturable filters were developed. But I think Iím right, I think it was 1964.
Bromberg: You yourselves were not engineers, any of your people? This was a company of physicists?
Cross: Thatís exactly right. The only place that had any engineering in it was in the people who were responsible for the production of the units. All, throughout the whole history of the company incidentally, a lot of the work was government, funded by government research.
Bromberg: Like this ARPA contract.
Cross: And a lot of it was products of a variety that required so much development that Iím not sure whether it was actually a purchase order for a piece of equipment or whether it was a contract for the government. I never concerned myself with where the money came from. I just tried to figure out the best way of spending the money. And so, you know, it was a fundamental mistake. You canít fund a lot of R and D out of the sales that we were producing.
Bromberg: It would be nice to get a copy of that resume, a copy of the Gras(?) Q switch paper, if you have it around. At the end we can talk a little bit about whether you have any pieces of paper.
Cross: We looked through everything. I did have some sales brochures. I had one that showed Bill Fredericks, have you come across his name?
Cross: Bill Fredericks worked for Trion, or he worked for [???] and he was on that. There were never any pictures of me in any of the — Bill I think owns his own company now, doesnít he?
Bromberg: I have some notes on that which I donít have in my head. Somewhere I think I have some notes on that.
Cross: I suspect Peter Franken told you all about Alan Hill.
Bromberg: I havenít spoken to Franken yet.
Cross: Oh, you havenít?
Bromberg: Obviously heís on the list but I havenít, I donít know anything about him. I only know a little bit about Alan Hill from John Myers.
Cross: Oh yes. OK. Iíll tell you a little bit about Alan Hill. Heís also a student at University of Michigan, and according to what Iíve heard Peter say, youíll have to check this with Peter to be sure, because he was always very generous in claiming that if it hadnít been for Alan, he never would have been able, would never have accomplished the second [???] generation experience there. I donít know what it was because the two were working on campus and of course we were in our company. But Peter was always very generous to give credit to Alan for really laying the foundation for that experiment.
Alan Hill worked for Trion for a while too.
Bromberg: Now, have we all the interesting R and D that was done over — itís about four years. When did you sell, or go into receiver? I donít know how you went in, whether you sold or merged or what?
Cross: We sold all our stock. They bought all the Trion instruments and stock from the stock holders. I donít know what you call that but it was sold to them. It was a complete acquisition of the company.
Bromberg: Was that í64?
Cross: I believe it was.
Bromberg: So I guess my question comes down to, when, weíve got these saturable absorbing elements and got some work on neodymium, I just want to make sure that weíve got the major, even the minor R and D projects that you were doing during this time, because I donít know them all.
Cross: You left out one big one, which was the spectroscopy application. The way that that came about, I donít remember why I was working in Peter Frankenís lab, but the first experiment that we ever did was done with the Trion instrument laser here hooked up to Peterís power supply and capacitor bank, and was up on the 4th or 5th floor of Randall Lab, where he had his laser set.
OK, at this stage it was not a Q switch laser, it was just an ordinary long pulse laser, and for some reason we were focusing the light, ruby light down onto pieces of carbon. I think they were spectroscopic electrodes, and watching this nice white jet of light come out, and I donít remember who was there with me at the time. It might have been Lloyd. It might have been somebody else. But whatever, whoever was there, I looked at that thing or a combination of people looked at it and said, ďHey, I wonder if there are any spectral emission lines come out of that stuff?ď
You wonít get them out of carbon. Carbon in the air gives off CN bands which are molecular structure.
So we mixed up a little salt solution, and we soaked a tip of that thing in salt solution and put it in there and rigged up a little spectrograph and made a picture, Trion Instruments at the time didnít have a spectrograph. We used one of [???]. And sure enough, on that film were a couple of very weak sodium D lines.
We then, I donít remember whether we took any metal emission spectra after that day, or during that series of experiments or not.
OK, so we didnít know what practical use this would have, but they focus laser spot is extremely small, of course, and we thought, gee, this is a neat technique for microanalysis of samples. It works on anything because it doesnít matter whether itís refractory oxide or glass or rock or a piece of steel, the laser will blow that material out, and produce emission lines.
So we approached a couple of spectroscopy companies, one of which I know was Bausch and Lomb, and the other of course was Jarrell Ash, and people, it was difficult to communicate with people at that stage, the concept of dielectric breakdown, because when we talked to the people from Bausch and Lomb, they told us it would absolutely not work on glass because glass didnít absorb red light. Despite the fact, we showed them pictures of a beam coming out — now, I suppose you might call it multi-photon absorption or whatever. At that stage we called it dielectric breakdown. We said, ďThe electric field produced by the laser is so strong that it is not necessarily a quantum effect at all which causes the vaporization, you can describe it in classical terms as just putting too strong an electric field across a dielectric and it breaks down and vaporizes.Ē
Well, we were totally unable to convince, to interest the people from Bausch and Lomb, because the man who was in charge of the R and D at the time said it will not work on transparent materials. He had a closed mind on the subject.
Well, we contacted Jarrell Ash, and the man that we dealt with there is named Fred Brech, and he was vice president in charge of research, and he came and talked with us, and we visited him, we talked to their —
Bromberg: Where is Jarrell Ash, by the way?
Cross: Newton, Massachusetts, I believe. Itís now part of EG and G, who in turn might be part of somebody else now, Iím not sure what the arrangement is, but Jarrell Ash Corporation was and probably still is the, one of the foremost manufacturers in the United States of spectroscopic equipment for metal analysis. They sell to steel manufacturing companies, thatís their main bread and butter.
Bromberg: So it was a matter of going out there to meet them.
Cross: Going there, going out there and talking to them, running experiments —
Bromberg: You actually worked in their laboratory, to show them the —
Cross: Jarrell Ash is a company that knows how to make money. They didnít have a spare spectrograph at all. The only thing that they had available was ones that were in the production line. The only access we had was between the time that it falls off the end of the production line and the time that it gets crated.
So Fred on a couple, at least one occasion, was able to wiggle a week or so in that gap, OK, so that we could come and run experiments using their fastest spectrograph, because the problem was that the ruby by itself, the ruby laser by itself, while it produced this beautiful jet, OK, was not enough power to really give a strong spectrum.
Now, Jarrell Ash was interested in this laser micro [phone? film?] because one of their competitors manufactured a thing called an X-ray micro(?) I donít know who that is but Iím sure somebody does. And the X-ray micro(?), what it does is it hits the sample with an electronic beam and excites its X-ray emission, which it analyzes using an X-ray analyzer and determines what materials are there.
The problem with that system and what Jarrell Ash hoped to overcome was, one, the samples had: to be in a vacuum, and two, that system is not efficient for materials whose atomic weights are too light, because the X-rays are too long, so there was a certain cutoff point. I canít remember where it was. It might have been in sulphur or phosphorus or something, but it was a fairly heavy atomic weight element and the laser microprobes since it didnít depend, since their emission lines were in the visible, was why they were interested.
Well, so, we came there. We ran experiments and they were rather discouraged because even with their fasted spectrograph, the sample, the laser would work well enough with fairly low conductivity metals like steels, stainless steel, and you could get emission lines from materials like rocks and so on, but high conductivity materials like aluminum and copper, you just couldnít produce a jet. And even the materials in which you could produce soft a good jet, the emission lines were really very strong and this was where Peter Frankenís finally saved the day.
His idea was that the laser could be used as sort of a super-scoop, but should not be depended upon to give enough energy to cause the atoms to emit light, what you could do, you could use some other source to cause the emission, and what was tried was to take a small capacitor and charge it up, and put two electrodes a few millimeters apart, above the same pole, OK, and then when the laser produced the plume, the plume would rise up, the gap would break down, and you would get emission from the atoms which had been scooped up by the laser.
Bromberg: What was Franken at this point? Was he a consultant for Trion? It sounds as if heís heavily involved.
Cross: Heís a member of the board of directors, and heís a free consultant. I donít think we ever paid him anything. Couldnít afford it. Not at his rates.
Bromberg: It also sounds, you know, I began by just assuming that you did your actual research in some room fitted out with equipment in your own establishment, but it sounds as if youíre doing this kind of peripatetic research , some of it in Frankenís laboratory and some of it out at Jarrell Ash. What was physically going on?
Cross: Well, like I mentioned, I donít know why we were in Frankenís lab. We normally didnít do anything there.
Bromberg: I see, that was it.
Cross: It was just a fluke. It just happened to be that the system was set up and we happened to think of the idea of running a spectrum and we did it. Now, he might have had the apparatus set up for second harmonic generation, Iím not sure. But to the best of my recollection, I canít remember why we were there. We just happened to do it.
Bromberg: OK, but that wasnít a large part of your work.
Cross: No, that maybe was one day. So that was not the routine.
Bromberg: Mostly you did work in whatever your rental property was?
Cross: Yes, all in the rental property. What we did at Jarrell Ash was also a fluke. It was done over a rather brief period of time. And that was because we couldnít buy a spectrograph, and Jarrell Ash could not lend us one. As I mentioned we had to get into that little gap there.
I believe, well, I know exactly the sequence of events. We sent an engineer to [???] and some laser equipment out there, and he set it up. Then I came out a little later, and I donít remember whether Jarrell Ash ever paid us for doing the experiments or not. Iím not sure myself, I just donít remember.
Bromberg: But then with these electrodes, what kind of device did you have at this point?
Cross: Now, there was a dispute, and I, there were conversations between the people at Jarrell Ash and Peter Franken at that time, to which I was not party. OK. And there was a dispute as to which group originated the idea of the ancillary electrodes. It was not anybody from Trion. It was either somebody at Jarrell Ash or Peter Franken himself, and there was a patent fight about that. Iím sorry, Iím off on a tangent, I canít remember your question.
Bromberg: I was just trying to see — no, really, youíre not on a tangent, because I wanted to see how this spectrometer developed.
Cross: Oh, OK. Well, with Peterís, with this refinement, it was then possible for Jarrell Ash to market the device. And as it evolved, Jarrell Ash got almost the whole schtick and Trion Instruments got only a very minute part of it, because we sold them the laser part of it, suitably modified, OK, for what we essentially sold the laser to everybody else for, which was you know, four or five or six thousand dollars. Well, they took it and they turned it into this big monstrous system which cost $100,000, and their profit on $100,000 was a whole lot more than our profit on $5000.
Bromberg: You didnít get any profit on your idea?
Cross: Well, we didnít patent it. I mean, Peter got a patent on it. I donít know whether he ever got any royalties from it or not. But I was very unhappy about it, because what they did is; we had a kernel which was absolutely essential to operation of this device, which was the laser. Without this laser, all the rest of their equipment would not work. But of course, they had human safety to worry about. They had to worry about how youíre going to handle the sample, how youíre going to get the lighting of the spectrograph, how can you be sure when somebodyís looking at the sample surface, the laser doesnít go off and hit them in the eye, and so on and so on and so on.
Whereas — so, essentially, they ended up withÖ (off tape)
Bromberg: Was this all with a ruby laser?
Cross: Yes. The ruby laser turned out, became Q switch, for better evaporation of the sample.
Since it had been assigned the job of super-scoop, it wasnít necessary to have as much energy out of the laser as was required when it had to both scoop out the material and excite it. The refinement of that in the auxiliary excitation makes the requirements on the laser much smaller.
Bromberg: So that was a big R and D effort.
Cross: Yes, it was.
Bromberg: There are a couple of things I wanted to ask, and there probably are things that you, we might just take a while to talk later about what else you want to say. Iím wondering whether there were other groups, I mentioned Ford but other groups, that you were working with outside the company that we ought to talk about, the way you worked a little bit with Franken, the way you had interaction with maybe other people on the board of directors, and Iím wondering about where you were situated with respect to the competition? We talked a little bit about your $5000 versus somebody elseís $25,000, but among firms like Hughes and TRG and Korant for example, Iíd just like to get some feeling for what the business environment and the competitive environment was like.
Cross: To tell you the truth, I havenít the slightest idea.
Bromberg: So these are questions I really ought to ask Linn, for example.
Cross: Yes. Or Lloyd. Iím not exactly sure when firms like Hughes and Korant began commercial production. Do you know when they began?
Cross: Hughes doesnít sell solid state lasers anymore. Did they at one time?
Bromberg: Well, I donít know enough about Hughes. Korant I think of as selling everything, and starting around Ď61, but again, I have no contact.
Cross: I think it was a little later but I donít know.
Bromberg: TRG I know did sell ruby lasers, because the Red Eyed Vireos — OK, so anyway, you werenít at that point paying much attention to the competitive situation. I wanted to find out about how; about the selling to Lear(?), you know, what happened. In that case, I would like to get some feeling for the factors that made it difficult for these early laser firms to survive, and I would like to look at that from that point of view.
Cross: OK, what made it difficult for them to survive was, there was no commercial market, like for years and years they said that the laser is a solution looking for a problem. Well, nobody had found the problem early on.
We did not have the reputation of a place like Hughes or Korant. We were horribly undercapitalized. We should have been able to run, well, thatís why we sold to Lear. They had the funds to do that. And it was very well demonstrated that you could not survive selling only to people who had a scientific interest in lasers. Thatís all there was at the beginning. What can you do with a laser? Well, you can shine it at a nice spot on the wall; you can burn a hole in something. It took a lot of refinements before people could get a ruby laser that would produce a hologram.
Bromberg: Were you involved at Trion in holograms?
Cross: No. I was not.
Bromberg: So you didnít have enough sales and you didnít have enough capital investment.
Cross: Thatís right. We didnít have enough capital to last over the low sales period, and we didnít — I donít know whether this is a proper judgment or not — I donít know whether we had an adequate sales force to be able to push the units that we did have. So we got superseded by people with more money and more intelligence, who could bring it out, could do the job better, could get you know, more longer lasting government contracts that could fund more people, and sort of boot themselves into existence.
Bromberg: Now, who was this receiver(?) and how did they approach you? Was it their approaching you or?
Cross: I havenít the slightest idea. Youíll have to ask Lloyd.
Bromberg: OK. Iím going to turn this off and just...
Weíve now decided what we want to talk about.
Cross: I want to put this down for the final record, and also put the answer to anybody who has ever heard about the green machine. Now, the green machine, presumably, and youíll find lots of people who will tell you that it existed at one time, was a super-frequency doubly neodymium laser, presumably I believe made by Korant for a control laser, for holographic purposes. No, this laser was supposed to be a solid state Q switch neodymium with a one meter coherence level.
Bromberg: And the color was green?
Cross: The color was green. I mean, neodymium light when you frequency double it gives you green light. It never existed. There never has been a green machine. They never built one. They never sold one to anybody. If you ever ask somebody, they will say, ďOh, Joe down the hall has one,Ē so you call Joe down the hall, ďNo, I think Al over in Building 22 has one,Ē so you call Al.
Because I tried to trace one down. I wanted to find out somebody who had bought one. Maybe I could look at it and figure out how this thing was built, how they got that very long coherence length, because presumably, see, this was an early machine, about Ď65, í64.
Bromberg: Where did you hear this? What made you think it existed?
Cross: Because there are a lot of people all over the country will tell you — because there are ads for the green machine. Thatís what happened. Some advertising person put out, probably in some place like [???], ads describing this miraculous green machine. And people saw that and were impressed by that. It really would be a fantastic device, if you could record — I mean, nowadays itís not so fantastic, but at that time it really would be fantastic device. You could get have made holograms, single pulse over very large objects, and in a few nanoseconds with a long coherence length.
So some advertising genius prepared ads and they actually were published. Thatís why, when you talk to many people in this business they will have heard of the green machine, but when you come right down to it, and I think Iíve exhausted the possibilities by going all the way back to the man at the factory who is supposed to have built the thing, and they just, you know, itís just a very difficult thing to do and they never managed to accomplish it. But it was advertised.
Bromberg: Some misunderstanding with the advertiser.
Cross: Yes. Right. So that should stomp the green machine idea.
Bromberg: OK. Now you said some of the interesting things that happened after receivers took over the assets of Trion. We just want to round that out
Cross: OK, well, I think, to the best of my recollection, the final perfection of a laser microprobe is manufactured by Jarrell Ash. It occurred during that period of time, not previous to that. And some more people joined the company that was interested in carbon dioxide lasers, which had been developed. Alan Hill ran some experiments on very high megavolt generators for pulsing CO2 lasers, and his experiments were later superseded by a more modern method of transversely exciting the CO2, exciting the CO2 with a transverse electrical discharge rather than a longitudinal one.
Bromberg: — Were you consulting now or working intimately?
Cross: No, I was working — well, after the spring of 1966, until the fall of 1967, I worked like I was an employee but I was paid like I was a consultant.
What I was doing at that stage was, we had a contract — no, we had contracts — to tell you the truth, Iím very vague on what the ultimate purpose was, but the thing that I was trying to do was to develop a similar optically pumped Q switch for the neodymium laser like we had developed optically pumped for the ruby laser.
What we found — let me go back a step or two. Once we had found this effect with uranium glass, Q switch to ruby, came the question of, why does it do that? Why does it do a lenses optically pumped? It must be due to transitions from some excited states which are populated by pumping the flash lamp to some still higher state.
That kind of phenomenon had been observed with dyes, dye solutions, before, but had never been observed in a solid material before. This was way back before there were, before anybody had ever done any experiments on excited state absorptions. Now those experiments are common.
Well, anyhow, what I did, that was the basis of my thesis research at the University of Michigan. I worked for a man in the chemistry department. His name is Thomas Dunn. When I described the work that I wanted to do, heís a molecular spectroscopist and I said, this is a molecular spectroscopy problem, and there was a pretty good overlap.
The result of those experiments demonstrated that uranium glass could never possibly lase because it absorbed its own fluorescence.
Using the same apparatus, I ran some experiments on trying to get an excited state absorber for the neodymium laser, and demonstrated a dye called rose bengal, dissolved in glycerin. When you optically pump that dye, it absorbs neodymium light.
Now, thereís a reason why — you see, if you just stick a — well, if you have something like a ground state absorber, and the only ground state absorber that I know of is the cadmium sulphide glass, the problem with that stuff is several fold. One, itís a rather weak glass, and itís possible to damage it if the laser beam is too intense. Secondly, the absorption edge of the cadmium sulphide shifts with temperature, so — and it shifts, unfortunately, to longer wavelengths, which means that more and more ruby light is absorbed , the hotter it gets. OK, so you fire the ruby laser once, the operation is fine. But the glass is left with a residual temperature rise. Hit it the second time, a third time, and this edge shifts down, and itís not a very acceptable material.
On the other hand, the uranium glass that we found for ruby was completely impervious. We never saw even the most intense laser beam ever damage that glass, including the 1.5 meter watt laser that was built. The glass was employed as —
Bromberg: — built by you?
Cross: Yes. At Trion. Or another company, Iím not exactly sure what the company name was at the time it was built. I think it was Trion but Iím not sure.
So we wanted to find similar material for the neodymium laser that would perform that same action. So thatís what the majority of my efforts were spent attempting to do, during that period when I was a consultant for them. In fact, I continued on after the company broke up. I had a one year extension to continue that work at the university I went to.
Bromberg: — who was funding you to do that?
Cross: I donít remember the name of the company. It might have been Lear-Seigler.
Bromberg: I see, but it was a company.
Cross: It was a company. Yes, it was the receiver. Essentially what it did in the summer of Ď67 was, they just closed the whole operation down. They decided that theyíd already lost enough money on it, and they decided that it was never going to be profitable. And in fact, I suspect that the ruby laser business isnít very profitable. And it never will be. There are far more profitable things; helium-neon lasers you can get into if you want to make money, because they well hundreds of thousands a year and itís a real production operation.
Bromberg: But Trion really sounds interesting. It sounds almost as if a bunch of people wanted to develop equipment. Itís like a little university engineering lab that just sort of floats as a commercial company.
Cross: Well, Iím getting my second chance at doing that. Thatís what my new company is intended to do.
Bromberg: One of the things I want to do is make sure I have your new company address.
Cross: Why donít I just give you a business card?