Stability Problems - Cured!

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Jem

Stability Problems - Cured!

Post by Jem » Sat Sep 04, 2010 3:16 pm

Hi all

Well, maybe I should say 'improved' until such time as my setup is fully proven capable of good results. You may recall that I am limited to producing holograms in my converted garden shed. It's completely insulated and reasonably temperature stable as long as it's not ridiculously hot outside. The problem I was having was that my small 1000mm x 600mm optical table was just sitting on a workbench, thus it was subjected to every movement in the wood structure of the shed.

So, I first set about cutting some holes in the shed floor in order to get to the 1 foot thick concrete slab underneath the shed.

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Then I cemented some concrete blocks to form two pillars, there is a ¼" gap all around the pillars to isolate them from the structure of the shed.

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Next, I put some high density foam on the pillars (similar to sorbothane) and put my optical table in placce.

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Then I let everything settle and dry out for a week. Once I was pretty sure everything had settled I set up a Michelson interferometer. Thankfully I was getting reasonably stable fringes, a small amount of drift was present but that disappeared after another couple of days.

So, then I set up to make a transmission hologram, adjusted the beam ratios, loaded a 2½"square BB520 glass plate and let everything settle for an hour or two. I then exposed and processed the hologram...

RESULT!!... The best H1 master transmission hologram i've ever made. The reconstructed object is really bright, in fact it looks brighter than the original model.

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So, inspired by my new success i've just stripped the table and setup for making a split beam reflection hologram. I'm going to leave everything to settle for a good few hours, but maybe tomorrow i'll do a test exposure and hopefully get a decent result. If that works i'm then going to try a H1 to H2 copy which i've never done before due to the problems I was having with stability.

Cheers

Jem

rzeheb

Stability Problems - Cured!

Post by rzeheb » Sat Sep 04, 2010 9:43 pm

Congrats Jem. It's a great feeling isn't it? About a year ago I visited with Dave. He showed me his lab and some of his holograms. I ooh'd and aah'd and felt that I would never be able to achieve anything even close to the brightness and clarity of his display holos. He urged me to concentrate on the fundamentals (table stability, settling time, beam ratios, blocking air movement) and bit by bit my quality would improve. He was right! My H1 to H2 holos have finally gotten to the point that I don't even mind showing them to anyone other than my family. I even have a few on my desk at work. Oh, and BTW, I followed your tip and bought a few of the Jansjo LED work lights from IKEA as sources of illumination. They work great. For anyone else reading this IKEA recently reduced the price of these lights from US 39.95 each (the first one I bought about 3 months ago) to $9.95 each the next 4 I bought about 3 weeks ago)! Highly recommended, thanks for the great suggestion! Ron

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