405nm- any progress

jsfisher · Post by **jsfisher** » Fri Jun 07, 2013 1:41 pm

Jeffrey Weil wrote:It's not a good idea to limit the power going into the module to lower its emitted power. There's other things in there that need the full voltage or current to work correctly, tec's, chip, etc....

Usually there's a small pot inside these things to limit the current going to the diode itself. That's a much better way to adjust the output.

Also, if your planing on getting a few different power supplies it's probably a better deal to get a proper voltage and current limited bench supply. You can get them for under a hundred bucks and it'll run everything you throw at it.

I think you may have misunderstood my intent. The controller I was referring to is essentially that same as in the links Dave provided. No tec, etc. The controller deals only with current regulation to the diode itself.

Jeffrey Weil · Post by **Jeffrey Weil** » Fri Jun 07, 2013 2:51 pm

Sorry I misunderstood JS.

Dinesh · Post by **Dinesh** » Sun Jun 09, 2013 11:42 am

Martin wrote: Actually, ferric ammonium oxalate sensitized gelatin (FEG) seemed to provide better speed than ammonium dichromate sensitized DCG.

True. I did a test for Martin some time last year with FEG using a 457 and the results were quite good. Did not try 405, but I think for FEG, the bluer the better. By the way, the hologram is still visible with no lamination since September or so.

Martin · Post by **Martin** » Mon Jun 10, 2013 3:45 am

Dinesh wrote:True. I did a test for Martin some time last year with FEG using a 457 and the results were quite good. Did not try 405, but I think for FEG, the bluer the better. By the way, the hologram is still visible with no lamination since September or so.

That doesn't sound that bad.
When it comes to 457nm recordings I still think that there are some ferric compounds out there that have far better absorption at that wavelength than FAO. For example ferric ammonium citrate (FAC), the "green" kind, would be something to try.

And in regard to speed of ferric systems, relative humdity in the recording environment may play some role. Switching to summer mode, the increased RH in my lab (currently ~ 80% compared to ~40% during the winter season) seems to enhance photospeed of FEG systems.

dannybee · Post by **dannybee** » Mon Jun 10, 2013 9:28 am

" I've tried DAS, diazidostilbene-2,2'-disulfonic acid salt"

Is there any formula for this? and what is the process? sites or papers talking about the process?

Dinesh · Post by **Dinesh** » Mon Jun 10, 2013 4:53 pm

Martin wrote:And in regard to speed of ferric systems, relative humdity in the recording environment may play some role. Switching to summer mode, the increased RH in my lab (currently ~ 80% compared to ~40% during the winter season) seems to enhance photospeed of FEG systems.

I've just looked up my records and I see that I recorded it in March 16th 2012. The humidity on that day was 43% and the temp was 70 F ( ~20C). I have no efficiency figures, since it was a display.The notes for the hologram show that the power at the plate was 2.1 mW and I initially tried 60 seconds, which I noted as "almost nothing", then I tried 120 seconds and I noted that it was "good". I remember that at the time you thought that this exposure was a bit on the high side.

dannybee wrote:" I've tried DAS, diazidostilbene-2,2'-disulfonic acid salt"

Is there any formula for this? and what is the process? sites

We tried using diazo dyes at POC sometime around 1987. As I remember, the holograms were a bit weak and it was abandoned. Probably by now, techniques have improved.

dannybee wrote:papers talking about the process?

http://www.benthamscience.com/mats/samp ... 0Samui.pdf
http://oai.dtic.mil/oai/oai?verb=getRec ... =ADA076203
http://en.wikipedia.org/wiki/Azobenzene (go halfway down to "Photoinduced motions"
http://www.dtic.mil/docs/citations/ADA297569

Martin · Post by **Martin** » Tue Jun 11, 2013 3:33 am

Dinesh wrote:I remember that at the time you thought that this exposure was a bit on the high side.

Yes, compared to 405nm exposures. Perhaps dealing with FAC or other ferric salts may improve the situation for blue recordings.

Martin · Post by **Martin** » Tue Jun 11, 2013 3:35 am

dannybee wrote:" I've tried DAS, diazidostilbene-2,2'-disulfonic acid salt"

Is there any formula for this?

Not to my knowledge. I simply added as much DAS from a stock solution to the gelatin solution I could.

Light absorption seems to be in the UV - blue-violet spectral range only.
Otherwise, the liquid processing is similar to FEG systems. One pecularity though is that on the laser exposure the layer slightly darkens (but that effect vanishes after the liquid development).

and what is the process? sites or papers talking about the process?

Kosar's book (Light-sensitive systems: chemistry and application of nonsilver halide photographic processes) extensively treats diazo processes.

dannybee · Post by **dannybee** » Tue Jun 11, 2013 8:59 am

thanks Martin and Dinesh,
whats the formula & process for FEG systems and are the chemical easy to find?

jsfisher · Post by **jsfisher** » Tue Jun 11, 2013 12:49 pm

I'll plug the wiki any chance I get: http://holoinfo.no-ip.biz/wiki/index.ph ... um_Oxalate