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Holography: how do to expand HeNe beam for Denisyuk Hologram?

Leek-leek5

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I'd like to you my Hene laser to create simple Denisyuk Hologram.

But I have no Idea what inexpensive lens to use to illuminate the 5" square plate.

I've seen people use concave mirror, double concave lens, microscope objective lens. Can I pick up any regular degular version of these from eBay to create holograms?

Links to products would help so much
 



Anthony P

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I try to use a front surface convex lens to spread the beam whenever possible. This avoids any imperfections caused by lenses. Your subject will need to be something bright, light in color. Coins work well for a first attempt. Good reflection holograms are difficult and require multiple beams. I am sure Paul will weigh in on this topic.
 

paul1598419

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Hi. I think Tony meant to say he uses a first surface convex mirror instead of saying "lens". This works best as all lenses introduce some noise into your hologram and usually need spatial filtering if used. But, for a simple refection hologram you might be able to get by with a lens without introducing an objectionable amount of noise. The FL isn't that important as you can always move the lens to produce the amount of illumination you desire. By 5 inches square, I'm assuming you mean 5 inches along one side. That is actually a 25 inch square plate.

I would use white objects for your first hologram as they reflect light well without adding specular reflections into the mix.
 

Leek-leek5

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Would this work, if not could you link me to something that would

Hi. I think Tony meant to say he uses a first surface convex mirror instead of saying "lens". This works best as all lenses introduce some noise into your hologram and usually need spatial filtering if used. But, for a simple refection hologram you might be able to get by with a lens without introducing an objectionable amount of noise. The FL isn't that important as you can always move the lens to produce the amount of illumination you desire. By 5 inches square, I'm assuming you mean 5 inches along one side. That is actually a 25 inch square plate.

I would use white objects for your first hologram as they reflect light well without adding specular reflections into the mix.
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paul1598419

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No. That is a regular mirror with glass in front of the mirrored surface. That will introduce extra reflections off the front surface of the glass. Also you need a front surface mirror that is more convex than that one is. You want it to spread the beam out without taking a long distance to do so. These are not often easy to find as they don't have a lot of other uses. I would try a couple of lenses it you can't find the mirrors. I usually spatial filtered my reference beam, but it is not necessary on the object beam. Remember you need your reference beam to strike the plate at the other side from the object beam. You will have to play with exposure times as that is dependent on the power of your HeNe laser and the type of film plate you use.
 

Anthony P

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Yes, I meant mirror not lens. I get mine at Edmund Optics, but they are not cheap.
An appropriate diode laser with no collimating optics can be used for a simple single beam reflection type.
 




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