Problems with Holograms and Bayfol HX200

[lavidadetomas]

Hello, my name is Tomás, I'm from Spain (Sorry for my english) , and I'm a complete beginner. I need help, thank you very much.
I'm using Bayfol HX200 films and I'm having trouble trying to make a hologram with them.
When I expose them for about 15 minutes, the film shows nothing, and they end up looking like this:

0.png (1.41 MiB) Viewed 3506 times

I'm trying to make a reflection hologram and have attempted these two configurations, one with the laser tilted sideways and the other facing forward:
Angle 0 degrees :

1a.png (691.6 KiB) Viewed 3506 times

1b.png (498.34 KiB) Viewed 3506 times

Angle 30 degrees:


I'm combining three lasers—red, green, and blue—using a cube-shaped prism to turn them into white light.
The lasers I'm using are these:

Blue laser: Wavelength: 450nm, Output power: 50mW (https://es.aliexpress.com/item/1005005443651774.html)
Green laser: Wavelength: 532nm, Output power: 50mW (https://es.aliexpress.com/item/1005006766368719.html)
Red laser: Wavelength: 650nm, Output power: 50mW (https://es.aliexpress.com/item/1005007095024469.html)

Then, I'm using a convex lens to try to expand the laser beam. I've tried both with and without the lens, but the beam only expands slightly. This is the lens I'm using: (https://es.aliexpress.com/item/1005004695818875.html)

I'm attaching the Bayfol HX200 films to a flat transparent plastic film to keep them from moving. This is the one I'm using: (https://es.aliexpress.com/item/1005007767809421.html)
However, when I remove the protective layer from the Bayfol and stick it on, it ends up with a lot of bubbles, which makes it quite difficult.

I'm doing everything on a very heavy granite block to avoid vibrations.

Some films even have marks from the light or from the clip I'm using to hold them:


What should I change?

Here are more photos of my setup:


Thank you very much.

[Joe Farina]

Welcome to the forum Tomás.

Almost certainly, the lasers do not have enough coherence. Have you previously made holograms with these lasers?

You might want to try one of Dave's lasers (532nm) to get started with:

https://holographyforum.org/forum/viewt ... 2&start=70

Other than Dave's inexpensive laser, there are some other reasonably-priced alternatives for a 532nm laser with enough coherence to make holograms. I know that color is your goal, but I think it would be best to start with a single laser. Then you can make a few holograms and be certain that everything works.

If you're attaching the Bayfol film to plastic, I would use glass instead. It's more stable. It looks like your metal binder clips are attached to wooden dowels(?) Wood may warp/move during the exposure (due to moisture absorption/evaporation). Metal rods would be far better. If you're using a polished granite slab, then you might be able to dispense with the rods altogether. The metal binder clips might be able to stand upright on the granite without the extra help of the rods (although the clips and granite slab look a bit small for this purpose).

Edit: I just noticed that the block appears to be granite with a rough surface(?), so the binder clips may not be able to stand upright on this by themselves.

I would also place the objects much closer to the film, almost touching if possible. Hope this helps, and good luck.

[Din]

I agree that the lasers probably don't have enough coherence.

Also:
1. The film should be secured better. If you simply attach the film to a single sheet of plastic with two clips at the bottom, the top of the film/plastic will move. You should attach the film between two sheets of glass, and have multiple clips on the sides and the top. Note also Joe's comment about wooden dowels; what are the dowels attached to at the other end? Long thin rods (wooden or metal) will bend if there's a weight at one end supported at the other end on something unstable. If the back of the rods are attached to something stable, the rods should be touching the edge of the film/glass, not attached to the clips. The (attached) rods will give greater stability to the film/glass. Also, the setup seems to be on some kind of carpeting, which will cause motion. You should paint the granite block black, to avoid reflections from the granite surface, then stabilise the plate/film with the rods (properly attached to something stable), and have multiple clips with the film sandwiched between two glass plates. I think the film is too large for the setup, it looks like the plastic is about 20 cm by about 25 cm. It's very difficult to keep such a large piece of plastic, or glass, stable. I'd try smaller film, about 7.5 cm by 7.5 cm to start with, and increase as you get images. Consider gluing the glass-film-glass sandwich to the granite block with hot glue.

2. It looks like the objects are not reflecting your laser colours. I see a green shadow from your object setup, which means some colours are not reflecting; the shadow should be black. Also, the objects are facing away from the film, so that the light reflecting from the objects are missing the back of the film.As much light as possible should hit the back of the film. I'd start with just one colour, as Joe suggests, with no cube. Back in the old days we had what we called the KISS philosophy - Keep It Sweet and Simple (there were other words, not so polite!). The objects themselves should be stable - consider also gluing the objects onto the granite

3. the reference beam should not be at zero degrees. The reason is that the light(s) will hit the front of the film and reflect from the back of the film - you end up with a holographic mirror, not a display hologram. Also, it's impossible to view the hologram, as the recon light will have to come from the back of your head. Most holographers have a reference beam angle at about 60 degrees (in keeping with KISS, rotate the film instead of moving the lasers.)

4. Be sure your cube is not a polarising beamsplitter

[Valery]

Какое бы было счастье у всех голографистов , если бы эти лазеры и за такие цены могли работать для получения голограмм. !!! Единственное что можно попробовать с ними записывать копии с мастер голограмм вплотную прижав ее к мастер голограмме денисюка и то со стороны эмульсии чтобы разность хода опорного и предметного луча была бы минимально возможной.
Мой совет поговорите с Филом, он поможет подобрать для вас соответствующий лазер но это будет гораздо дороже.
Желаю вам не отчаиваться и прдолжить эксперименты , судя по фотографиям вы серьезно относитес к возможности получить голограммы. И конечно,Ю начните с монохрома. Т.е. с одного лазера.

[Martin]

Here is a good summary:

Choosing Lasers for Holographic Applications
Written by E.k. Illy, H. Karlsson, G. Elgcrona 24 September 2018

https://www.novuslight.com/choosing-las ... N8352.html