Maybe, at that moment of time making a distinction between "HOE" and "display" simply made no sense. How many display holograms had been recorded at that moment?Dinesh wrote:The problem I'm having is: Did Denisyuk think he was making a hologram of a mirror or a holographic mirror. In one case, it's a display hologram, in the other, it's a HOE.
Johnston (p.71) points out: "Strictly speaking, the scatter in Denisyuk's implementation is more properly described as specular or mirror-like reflection. He had not attempted to record diffusely reflecting objects."But, the paper doesn't make it clear since it talks of a "scattered field". However, scattering implies diffuse scattering from a diffuse object, reflection of light from a mirror (curved or not) is not "scattered radiation". If you tried the geometry in the paper, with a series of curved mirrors, I think you would get pure reflection and so a holographic mirror and no scattering.
Is that so? Denisyuk seems to have used a filtered mercury vapor lamp only. So the coherence length wasn't quite large.
Right. That really opens a Pandora's box. E.g. if there had been some dust particles on the reflector (not particularly unlikely), do those Lippmann photos morph into reflection holograms (are there "Denisyuks" before Denisyuk)?But, if you coated the mirror with a fine coating of dust, then the dust would scatter and you'd have a hologram of a mirror.
Yes, that would be interesting to know.Perhaps, there could be a little uncertainty in the translation from the Russian?
Johnston writes:The interesting thing is that Denisyuk himself was not consistent. When I asked him how he thought of the technique, he said that he had come back from vacation and saw a paper on Lippman photography. As he read the paper, he realised that the author did not completely understand Lippman photography. As Denisyuk was thinking of a response, it struck him that he could use the principle of Lippman photography to create white light reconstruction in holography. To place the conversation in context, I was talking to him about how strange it was that the laws of physics are so simple and he answered, "Yes, simple, but so difficult to prove". However Hans Bjelkhagen has stated that he (Hans) thinks it was because of a book that Yuri had read. Jeff Weil has told me that Yuri gave him yet another explanation of the origin of the Denisyuk technique.
"The inspiration for Denisyuk's ideas is unclear. (...) He recalls having been inspired for his thesis work by the writings of the Russian science fiction author Ivan Antonovich Yefremov."