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If the recording medium is thin, then there are fewer Bragg planes, and the variation of the spacing from the mean may be high (large standard deviation), resulting in a broad range of wavelengths. As the medium gets thicker, the variation from the mean gets smaller (the standard deviation drops), ...

PRATHEEP wrote: ↑Mon Dec 06, 2021 12:20 am washing is done with the same , its alright now ... but the main drawback "sensitivity" is very low …. how can I improve the spectral sensitivity?

Again, take a look at the pdf file at: https://holographyforum.org/forum/downl ... hp?id=7201

So if you aim at very narrow bandwidth, you'd need a thick (I think ~ 1 - 2um or so) recording medium. Volume gratings e.g. currently used to run compact ECL laser diodes at single frequency (see Ondax, now Coherent I believe) would come to my mind. Sorry for the typo. I meant 1 - 2mm thick recordi...

Typically, AgX emulsions are ~ 8 u. The micrometer you link to states a resolution of 0.001 mm, or 1u. Thus, it can measure an 8u thickness, but, with a resolution of 1u, the error is 8 +/- 1 or 1/8, or 12.5%. This is too inaccurate for technical work, but is not a problem for display. Agx has typi...

what are the effective washing methods for 0.5 and 3 % gelatin concentrated silver halide emulsion? and also how to improve the spectral sensitivity of the silver halide emulsion for 632.8 laser? In short: freezing and thawing as outlined e.g. at https://holographyforum.org/forum/download/file.php?...

Pretty amazing! Thanks for the info, Dinesh.

The final colour of the display piece can be varied, from the recording wavelength, to about 100nm, its a balance between formula, recording and development; this is because of the high dynamic range of DCG. We were able to get some pieces below the recording wavelength. I was wondering about that ...

I too suspect 405 is underrated for display work. My exposures in standard DCG with the 445 and 488 are easier to make bright gold than anything else, and this represents a rather large redshift from the recording wavelengths. It would seem that 405 would tend to produce great bright green replay u...

If my assistance would be useful in developing the technology, I would love to help. Please do. Any help will be greatly appreciated. Given the scarce experience with holographic diazo gelatin materials, this is almost pioneering work. Lasers on hand: 405, 445, 473, 488, 532, 568. Sounds impressive...

Din wrote: ↑Tue Sep 28, 2021 12:39 pm Here you go! I assume that 'without any spectral sensitization' means you are going to add ammonium dichromate

Yeah, absolutely