Help minimizing motion & can i skip the lamination?

[Jess]

Hi!

I'm pretty new to holography. I did a few attempts which failed - there was no image formed at all. This means that there's motion which is screwing up my results.

I think I'll do my next attempt late at night so my neighbors aren't walking around, but there's factors that I can't control, like wind noises. My first attempt was on a table which failed and i tried on the floor which also failed obviously. I also use a socket switch that i can turn on or off remotely. I wonder if the click sound when i turn it on would screw up my hologram?

I have a server running in the room next to the one i use for the holograms. It's not too loud but it does make noise. Would that also need to be off?

And final question, i use bayfol hx200 film. I tried laminating and also just putting it between two glass plates and holding them together with clippers. Both failed so i couldn't draw any conclusions, but I'm wondering if I could just not laminate it, and just use the two plates method. Would that work?

Pics of my setups and film sandwiched between plates: https://imgur.com/a/0KQMUDJ

Thanks!

[Din]

Let me start by saying that if you're doing a Denisyuk (which I assume you are) the entire setup - platemount, plate and object must not move by half a wavelength, which, for your laser, would be about ~250 nm. For comparison, a human hair has a width of 25,000 nm.

I think your setup is very unstable. You seem to have a sandwich of glass held together with binder clips resting on a shopping bag on a wooden floor. Your setup needs to be far more sturdy and without the glass plates held by the clips. The problem is that glass plates held by clips tend to flex and warp; it may not seem so to the eye, but remember motion must be limited to ~250 nm. The bag is loose and will cause motion, the system must be solid, not placed on cloth. Also, the server creates hums, which disturbs the air and causes vibrations.

So, firstly, you should laminate. This is a tricky procedure to do in the dark and you'll get bubbles, but, if you get a hologram, you can fine tune your laminating as you go along.

Secondly, there are two ways to hold the plate I can think of in your situation:
1. Get a slab of granite from some granite yard who may have leftover slabs. The slab should be about 2' x 4'. Get, or make, a U tube with three sides enclosed and one open to place the plate. You should try and secure the plate within this plateholder somehow - screws drilled into the U tube, for example. Now place the laser at one end of the 2 x 4, and hot glue the plate holder and object to the slab - the idea here is that if there is motion, everything moves together, the motion problem exists because of relative motion of the parts of the system. Make sure that the slab does not rock as you tap it.
2. Get a large plastic storage bin and fill it full of sand. Stick three rods into the sand forming a triangle with the tops about even height. Place the object on the sand below and place the plate on the three rods so it's level. Shoot overhead - the plate is now horizontal and the laser is coming in from above down onto the (horizontal) plate. The laser should be placed on a secure base, and the beam has to come down at an angle towards the plate.

[Jess]

Would a heavy flat piece of wood work?

[Joe Farina]

If you're using HX200, which is a slow material compared to silver, then I would avoid using wood. As a table, you can use a concrete paving slab from the home center, resting on a bicycle inner tube. The floor appears to be wood, which isn't ideal, but may not cause a problem. I don't recommend sandwiching the film between glass. I would just laminate it to glass using a cheap rubber roller. There will be bubbles as Din said, but practice will improve the results. The method of holding the plate firmly on the table is important. It needs to be quite stable. Personally, I use three pieces of half-inch marble (stone) which is available at the home center. The bottom is the base, and the two upper pieces are cemented together to form a slot which fits the glass carrier-plate precisely (which is easy to do because the two upper pieces are cemented in place). Then I simply insert the glass plate (with film laminated to it) in the slot. For the cement, I use mortar (Portland cement and sand). Using the paper clips (as in the photo) could conceivably work, but it looks like your location is less than ideal in terms of stability, so I don't recommend using them. Are you sure your laser can make holograms?

[BobH]

Would a heavy flat piece of wood work?

For Denisyuk? Yes.

I'd use any room except the server room. Too much noise, wind, and vibration. Also, skip the fabric base. Mounting is better than pinching the film. Try heavy metal parts instead of books for weights. Concentrate on three-point stability between film plate and object. Finally, try a beam block shutter instead of turning the laser on and off. Just some suggestions.