Graube paper

Dichromated Gelatin.
Martin

Graube paper

Post by Martin »

Some more details about Graube's work at Hughes Aircraft:
http://www.dtic.mil/dtic/tr/fulltext/u2/a020945.pdf
Dinesh

Graube paper

Post by Dinesh »

This takes me back! My colleagues and I at NTS (National Technical Systems) worked on this in 86 or so. A lot of my colleagues in the the research dept at NTS went on to Hughes Research, Malibu and continued working on it.I remember my first interview at NTS, in April 1986. At that time I had only just come to the US from England, mainly working on display holography at Richmond Studios. I showed up at NTS for my first interview and was asked if I could make holograms. Sure. Of what? Then the interviewer showed me an Air Force helmet and said, "Can you make a hologram on this?" I had heard of Holographic Optical Elements that had to be shot on dcg, but I had never shot one or shot anything on dcg. Dcg was also supposed to be very difficult to shoot on and very difficult to get consistent results. I told the interviewer that I had never made a hologram on dcg and I had heard of holographic optical elements but had never seen one, much less made one. So, he gave me a spec of sorts of what he wanted. I said, "My best guess, and it is a guess, is that you need a point scatterer at f behind the helmet where f = <this> and a beam divergence of <this>" So, he asked about the f and theta, and I made a back-of-the-envelope calculation on a whiteboard in his office. The interview was 4 o'clock on Friday and he said, "Can you start in about an hour?" He must have seen the disbelief on my face, because he said, "Kidding. Start on Monday morning". It was one of the finest labs I'd ever worked on because there was no rivarly in the labs at all. We each had our specialty and we respected each other's specialty. I was the physics/math guy, there was a chemist, a mechanical engineer, and an aeronautic engineering student. All of us held together with a lab manager and a VP oi research who mainly kept out of our way and let us pursue our own solutions to the technical problems. Back then, we had polymers on dia-zo dyes from the chemist, I came up with an idea on making holograms on lcd (very new back in 86) and the mechanical engineer came up with a scheme to measure a specific gas at a few parts/million in air.

In the end, there were so few papers or written material on dcg, that we had to pretty much "wing it" on most of the shooting parameters and the development schemes. The chemist designed development systems and worked on new materials like di-azo compounds, I worked on the physical parameters like emulsion depth, back tracking the fringe modulation from the spectral plots and then design a recording scheme. I remember coating those helmets was a real challenge and the aeronautical engineer found an elegant solution.
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