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:



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 :



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.

[laserist]

Hello Tomás, I don't know much about holography, but I'm pretty sure you need to light them from same angle you made them from with a bright light and view them against a black background. It really looks like the light mostly never hit your target in the photos...

[absolom7691]

I also don't have much knowledge in holography but I thought diode lasers gave pretty unreliable results due to their instabilities compared to other, better laser choices. It's one of the reasons people still use linearly polarized HeNe's and other very stable SLM lasers. SLM OPSLs are a good choice with green OPSLs being very affordable in the <100mw range. The DPSS laser you have is probably better suited than the diode lasers.

The fact that you can see the clip on the film makes me wonder if you're just getting too much scatter and noise with an RGB laser setup. I'm also not sure how precise the alignment needs to be. Same goes for matched divergence, matched transverse mode, and even beam shape . Have you tried getting a decent exposure using just one wavelength? I would try with just the DPSS green first and see if you can get a decent exposure.

This forum also has a holography section. I don't know how much information you would be able to get from the posts there, but it's worth looking at. A few members here are quite adept at holography and have posted about their setups/equipment used. This thread might have some useful info for you: https://www.photonlexicon.com/forums...3901-rgb-laser. It looks like you already found the holographyforum.org because I see you posted there, too. You might get better/faster responses there!

[buffo]

It's a shame that Jeremy Turner (JEM) is on a cruise right now. I'm sure he could offer plenty of advice regarding this setup.

He should be back next week sometime though, at which point hopefully he'll comment here.

Adam