Can I use 5mrad?

This is a forum to share experiences and ideas about holography.
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Chanwoo

Can I use 5mrad?

Post by Chanwoo »

hello guys,

I find this for use. But mrad is too high than other lasers. Is it suitable for hologram?


http://www.cvimellesgriot.com/Products/ ... stems.aspx
Joe Farina

Can I use 5mrad?

Post by Joe Farina »

Yes, those lasers are excellent for holography. You can change the divergence using a Donders zoom telescope (3 lenses) as discussed in the recent thread on this forum "anamorphic prism pairs for the 445nm diode."

But if you intend to use this laser for color holography with silver halide materials, such as PFG-03C, the short wavelength of 458nm will cause a fair amount of scattering. Both Bjelkhagen and Gentet would proabably recommend using the longer blue argon wavelength of 470-something, I forget the exact wavelength. I'm planning to work with DCG, so the scattering issue isn't much of a factor.
Chanwoo

Can I use 5mrad?

Post by Chanwoo »

Thanks Joe,
I saw "anamorphic prism pairs for the 445nm diode" forum. I will prepare some optics.
I am glad to solve that problem as your opinion.
Joe Farina wrote:But if you intend to use this laser for color holography with silver halide materials, such as PFG-03C, the short wavelength of 458nm will cause a fair amount of scattering.
Even so, I am going to use this. I can't understand that you told exactly. Is that Noise?
Joe Farina

Can I use 5mrad?

Post by Joe Farina »

Chanwoo wrote:
Joe Farina wrote:But if you intend to use this laser for color holography with silver halide materials, such as PFG-03C, the short wavelength of 458nm will cause a fair amount of scattering.
Even so, I am going to use this. I can't understand that you told exactly. Is that Noise?
That should be fine. I have used (and really liked) the Melles Griot laser. No problems with etalons, water cooling, or three-phase power.

With regards to a scattering problem, maybe you don't need to worry about it. I remember seeing a side-by-side comparison of one of Bjelkhagen's color holograms made with 442nm blue, compared to exactly the same hologram made with a longer blue wavelength. Honestly, I couldn't tell any difference (these were on PFG-03C). But Bjelkhagen tends to be a stickler for very small differences in quality. He makes a pretty big deal about the scattering problem, but there may be no big difference bewteen 458nm and 476nm for display holograms, so I would go for it, and use the Melles DPSS.

Scattering of light off of small particles (such as the silver halide grains in PFG-03C) is more pronounced as the wavelength becomes bluer. This contributues somewhat to the noise level. I doubt that scattering noise would be much of a problem at 458nm for fine-grained materials like PFG-03C. But I honestly don't know, since I've never used blue light on silver halide. It might be a good idea to check Bjelkhagen's book "Silver Halide Recording Materials for Holography." I think there is a section on color holography, and I think he talks about the scattering problem.

They say the sky is blue because the blue component of daylight scatters off very small particles in the atmosphere.
Colin Kaminski

Can I use 5mrad?

Post by Colin Kaminski »

To understand why shorter wavelengths of blue cause more scattering please look at this theory:

http://en.wikipedia.org/wiki/Mie_theory

The result is a blue haze around bright objects.
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