Little old Lady

Present your work.
Mr Astro
Posts: 12
Joined: Thu Aug 27, 2020 3:47 pm

Little old Lady

Post by Mr Astro »

this was a test of r/g laser from Holomaker, on Geola Polymer , viewed under laser light :)
little old lady.jpg
little old lady.jpg (28.47 KiB) Viewed 5187 times
lobaz
Posts: 280
Joined: Mon Jan 12, 2015 6:08 am
Location: Pilsen, Czech Republic

Re: Little old Lady

Post by lobaz »

Is is a two colour single beam Denisyuk?
If it is, then it is impressive. With AgX it is difficult to reconstruct volume holograms with laser light.
Mr Astro
Posts: 12
Joined: Thu Aug 27, 2020 3:47 pm

Re: Little old Lady

Post by Mr Astro »

Yes single beam Denisyuk
lobaz
Posts: 280
Joined: Mon Jan 12, 2015 6:08 am
Location: Pilsen, Czech Republic

Re: Little old Lady

Post by lobaz »

Is it sensitive to angle of ilumination?
A common AgX volume hologram (Denisyuk type) illuminated by white light changes its color as the illumination angle changes. It is thus very sensitive to illumination angle for laser illumination - it either reconstructs well, or does not reconstruct at all.
But I have no experience with laser illuminated photopolymer Denisyuks.
Din
Posts: 402
Joined: Thu Mar 12, 2015 4:47 pm

Re: Little old Lady

Post by Din »

lobaz wrote: Sun Sep 13, 2020 2:29 am Is it sensitive to angle of ilumination?
A common AgX volume hologram (Denisyuk type) illuminated by white light changes its color as the illumination angle changes. It is thus very sensitive to illumination angle for laser illumination - it either reconstructs well, or does not reconstruct at all.
But I have no experience with laser illuminated photopolymer Denisyuks.
Depending on the bandwidth, if a Denisyuk is laser illuminated, then the image will vanish over a range of about 5 - 10 degrees. This is because when you twist the Bragg planes, the illumination is off-Bragg. With no other wavelengths in the reconstruction, no other wavelengths will become on Bragg for a narrow band set of planes. According to Kogelinik, you can still reconstruct over a range of about δθ = 5 deg and about δλ = 5 nm. The dephasing parameter, ξ, can allow a small range with lower efficiency.

Photopolymers are necessarily narrow band because they don't need wet processing. That's the advantage of polymer for technical holograms, but a bit of a disadvantage for display holographers.
Loic74
Posts: 51
Joined: Sat Aug 10, 2019 9:09 pm
Location: France

Re: Little old Lady

Post by Loic74 »

Nice work with the photopolymer, I found it more difficult to use it for RGB work than Agx.

In my experience, the reconstruction of volume Agx color holograms using RGB laser light is not difficult but the angle of illumination is likely to be different from the recording angle due to emulsion shrinkage, if any, and narrow like Din said.
Here is an example of my RGB Denisyuks reconstructed with RGB laser ligth: https://www.youtube.com/watch?v=BW12ktp8LmQ
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