Robert Hopkins

Bromberg:

What I want to do at this point is just ask your memories a little bit about this coherence conference and how it first got started, and since you were already involved in it before Emil began to work on it, I want to go back a little further.

Hopkins:

My first introduction into modern Quantum Optics was due to the papers written by Brown and Twiss. That’s how I first got into the subject. I talked to Parker Givens a lot about it. He explained to me that people were talking about it. This must have been way back — when did I approach you?

Wolf:

‘59.

Hopkins:

This must have been way back in ‘57, ‘58. It turns out this Brown and Twiss experiment was something that people didn’t understand very well, and it took Purcell to really straighten it all out. Brown understood it just instinctively and was able to do his experiment without really being able to explain it as well as Purcell did. That made me realize that there was a lot going on in optics that had been neglected, that people weren’t really thinking about. Of course Ed O’Neill said that a long time ago. So I decided I wanted to get somebody to help graduate students and keep us informed in this area; to take advantage of it. So I went over and saw you (Wolf) about it. I think it was after you came that this Rodney came around and asked us to put on a conference.

Wolf:

You mentioned a conference to me already when you visited at Manchester. Yes, in fact you told me that you would like that as soon as I get here we have a conference going, but of course we exchanged a few letters after that at Manchester. Definitely I was aware of this before I came to Rochester, because you wanted me to run it before I even got to Rochester. I was horrified that you asked me already to run it when I was still in England. So either, it may be that Rodney offered the money before I came to Rochester, or it may have been a short period in between the times you were seeing me.

Hopkins:

I can’t remember. It might very well have been. I was out trying to get money every place I could at that time. That’s probably the way it came about.

Bromberg:

Was that attractive? I mean, what’s the use of having money for a coherence conference? It isn’t really money you can use to —

Hopkins:

I was out looking for money for the Institute of Optics. That was a rough time. There was practically no interest in classical optics, and for the Institute of Optics we were having a lot of trouble getting support. I was out looking for money at the Army research labs to help support some of the program. And I might very well have said, “Well, maybe I’ll get support for this conference.” That was about all we could do at that time. I guess I was interested in it because it would help me get something going, some interest generated in it at Rochester.

Wolf:

May I interject one or two things here — first of all, you are aware that Dr. Hopkins was director of the Institute of Optics at the time. Secondly, Rodney, I think I mentioned when I talked to you once before, you could get a lot of information from him. He’s at NSF now. And the third thing is that Dr. Hopkins’ institution was right, that it was a good starting place for the efforts, because Rodney actually supported me. He was the contact. We made money from them for many years after the conference. You know, the money I had from the Air Force Office of Scientific Research was all through Rodney. It was the starting point.

Bromberg:

I see. In other words, it wasn’t that your institute was well supported by the Air Force before that point.

Hopkins:

We weren’t well supported. We had a lot of support for practical things, like designing lenses. That was my field; actually, I’m more of an engineer type. I got a lot of support to design optical systems, satellite camera systems, things like that, but I didn’t get any money to help support some basic research in optics and that’s what we wanted. I had to get somebody on the staff that was interested in that activity, and that’s how I happened to get Emil more basic optical research.

Bromberg:

I see. Because the thing that occurs to me immediately is Sputnik. That’s October, ‘57, so you’d think they’d be rushing in to pour money over you, but —

Hopkins:

Well. That generated a tremendous amount of interest in practical applied things. I had no trouble having support for myself in engineering, but I wanted the optics department to be more than just an engineering department. I wanted it to also be doing things in basic science. So we were trying to get support in that area, but I couldn’t get it for myself because I was just not that type. I was not a research scientist. I was more of an engineer. That’s how that conference got going, and then with Emil’s thoroughness and everything it was really successful. I guess, practically all the important people in that field came to that conference, and that, along with the fact that the laser was made to go within a few weeks afterwards, really got things going. There were several conferences from then on.

Bromberg:

I notice that you mentioned that originally you wanted it in ‘59, and I noticed a few letters, I think you were one of the correspondents, in Townes’s files, saying that you’d like to have it in ‘59 and Townes was saying, well, there was the Schawanga Lodge Conference on quantum electronics. I don’t remember exactly who was implicated, but somebody was saying we out to move this coherence conference a little bit.

Hopkins:

Was that the first time or the second?

Bromberg:

That’s the one that eventually was June, 1960. This is correspondence dating from 1959.

Wolf:

You know, soon after I came to Rochester, a committee was set up for this conference. You might have seen some correspondence about the committee.

Bromberg:

That’s right.

Wolf:

I still remember, Bendam was on the committee, and Carver, you remember?

Hopkins:

Carver’s the one I was trying to think of. He first explained to me the importance of a laser beam.

Wolf:

Carver’s the man, (crosstalk), yes, right.

Hopkins:

All right, I talked a lot with him, either after you came or before you came, I think before you came.

Wolf:

But the original idea was to have it earlier. But I just didn’t see how I could do it because Dr. Hopkins wanted me to organize it, and I didn’t see how, just having come to America, I could organize a conference. I thought I needed to understand a little bit more how things are done here. So in 1960. But it was very well timed. It was so close to Maiman’s experiments. Dr. Hopkins is right we had all the people here who really mattered in physics. We have been very luck since. We have now had 5 of these conferences. We still managed to get the people.

Hopkins:

The one I was the most impressed with was Purcell.

Wolf:

Yes, right. He was something.

Bromberg:

He was at that 1960 one?

Wolf:

Oh yes. He’s an amazing person.

Hopkins:

Townes didn’t make it to the conference, did he?

Bromberg:

No, I think Heavens gave his paper.

Hopkins:

Heavens gave his.

Wolf:

Yes, that’s right. (crosstalk)

Hopkins:

I remember that.

Wolf:

We have still some photographs of Purcell at the Conference; we have a few photographs of the conference. I remember, in one, in front of the blackboard was Hanbury Brown. (crosstalk) And Peter Franken.

Hopkins:

Franken — he was so young and ambitious, he was just like a high school kid. He seemed that way. He and Purcell got into quite a battle. I don’t remember now what it was about. Another very impressive person was Brown. Brown probably would have invented the laser all by himself if nobody also had done it.

Wolf:

He’s amazing.

Bromberg:

But he wasn’t working on it.

Hopkins:

No. (Everyone talking at once…) even if he had not known what he was doing In retrospect, when you think of it, it’s just amazing that the laser wasn’t thought up before that nobody had done anything about it before.

Bromberg:

But the maser was on everybody’s mind. Everybody was working on it.

Hopkins:

Yes, everybody heard about that. Parker Givens knew what a laser was and knew what a laser would be if they got it going, and that was way before 1960.

Bromberg:

Clearly from what you’ve been telling me, the Air Force knew what a laser would be. That’s why they were o interested.

Hopkins:

Yes, Rodney knew. He knew about stimulated emission and everything, echoing affects. It’s just, nobody ever got one going.

Bromberg:

When we said that it was kind of lucky that the conference was when it was, does that mean that the support of the Air Force, continuing support of the Air Force, was influenced by the fact that there was an operating laser?

Hopkins:

Well, the laser generated a tremendous amount of interest, renewed the interest in optics, revived the field, because it was almost dead before that, and there was very little going. So it was very important to the field of optics, and has been very important ever since. It was lucky for us that we happened to be involved in it right from the very beginning.

Wolf:

Yes, it helped us to get a little bit on the map, you know, because we had a conference with the title “Coherence” That was just about the time when everybody was asking what coherence was all about.

Bromberg:

The think is that you had all these electro-optic instruments that the military was interested in and everything, and therefore I’m surprised that you tell me that optics, there was nothing going on. I guess I kind of thought that the —

Hopkins:

It was revived in ‘60, because of the laser. The growth in electro-optics business is due to the laser and to photolithography for making of microcircuits, because almost all these electro-optical devices are made by the photo-lithographic process. There were a fair number of military applications in what you’d call electro-optics way back in the sixties, but we didn’t have transistors on mini chips, we didn’t have light sensitive diodes at that time.

Wolf:

I think what Dr. Hopkins meant when he said that there was nothing going on just before that is, nothing basic going on. There was very good lens designing, right, very good instrument building, right, but you meant more basic things.

Hopkins:

Yes. It was a very bad time for the Institute of Optics. We almost didn’t make it at that time. The Institute of Optics started in 1929, and it was made a separate institute because they knew that physics departments were not particularly interested in optics anymore and that it would die out if it were just put into a physics department, so Rochester put it into a separate department so as to keep it alive and it was called Applied Optics rather than Basic Optics, and it did very well. It got some of the very best students in the university in the thirties, before the war, and it did quite well after the war. But then in the fifties, we hit some pretty bad times. Radar was so important that everything was going to be radar as far as the military was concerned. I mean, everything in optics was going to be done with radar in the future, all weather reconnaissance, all weather forecasting, and we had trouble getting support for all branches of optics. I remember one time going down to the National Science Foundation, and trying to get them to support the building of a piece of equipment so we could measure the performance of optical systems. Basically it was measuring the performance using Modulation Transfer and Fourier Transform Theory. They had at that time matching grants. If the institution would put up half the money, they’d match it. They turned us down. We couldn’t get a cent out of the National Science Foundation for anything to do with optics. Wolfs work was the first work we ever really got support from the National Science Foundation for. From then on, it was easy.

Wolf:

I remember you telling me in ‘59 that the future of the Institute looked very bleak, that you hoped it would change when I come. I remember you telling me that.

Hopkins:

Well, it was, there was very little going on in electro-optics at that time. The big surge has been since the laser came.

Bromberg:

I see. I don’t have much information on this. I know that I was told that this was just about the time, for example, that American Optical was set to sort of expand into the electro-optical field because they had not been doing electronics, and that made me think that this whole field was beginning to open up in many ways and people thought there was money in it.

Hopkins:

Well, there was one development that was opening up quite a bit in optics. Fiber optics generated a lot of interesting optics. And American Optical was primarily interested in that. The acquired scientists like Eli Snitzer who was aware of research on lasers, and almost immediately after the Rochester Conference they got lasing in Niodiniur coped glass.

Bromberg:

— they were a big fiber optics.

Hopkins:

— got into fiber optics and a fellow named Eli Snitzer who was a leader in that field, a very good physicist, was at American Optical. I think it was around 1958 or ‘59 that the Bausch and Lomb Optical Company changed their name, from Bausch and Lomb Optical Company, they dropped the “Optical,” because it had the image that Optical was passé, there’s nothing left in optics. I think it was no more than two years later that the laser came along, and optics was one of the most profitable fields in physics.

Bromberg:

— did they change the name back?

Hopkins:

No, they didn’t change the name back.