Subtraction Holography

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Smac

Subtraction Holography

Post by Smac »

Dear forum.
I am currently working on a subtraction-setup (which should be easy..), that I can't get right.
The setup is using a plane-polarized (vertically) He-ne laser, a 632.8nm Half-
Wave retarder, a 95%/5% beamsplitter, some mirrors of good quality and a very
stable filmholder. All mounted on a Nitrogen hoovering TMC table. It all should
be ok, but its not. The objects currently used are two polished metal
lensholders, placed on top of two micrometerscrews. Both can be moved if
needed.
After reading about the subtraction holography setups in different papers, I
have tried a lensless Fourier setup, placing the two objects far from the film,
and close to the reference microscope-objective. So the object and reference
beams have similar curvature. So far I have not tried ordinary Fourier setups.
However, keeping one object in a fixed position, moving the other, and changing
the reference wave by 180 degrees (90 degrees movement) the fixed object are not disappearing. Very sadly!
Have any of you got any tips ?? I can send you picture of setup if wanted!
K.Rgds
Stian
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