Holographyforum.org / holowiki.org

So why did it take so long to come to light 💡?lol

So many complaints, people giving up holography all together even.

Convestro said “no no don’t use water “?

Because of these bubbles …

[quote=holomaker post_id=73860 time=1778102397 user_id=2175]
Hey u guys update to long history these bubbles . The. Current way to do this is under water , yes i said that UNDERWATER, don’t put on the scuba gear and jump in the pool ..lol but seriously use clean filtered water, do this in at least a pretty clean environment . Put 1” of water in a darkroom tray to fit your plate , drop in clean plate ,and gently remove the backing from the pp film and slide your PP into the water , with film cut slightly smaller than your plate, align it and gently roll them both togethers. if alignment is bad,remove and reset , once aligned roll lightly, remove the PP plate and now HARD ROLL all water out. Load your plate shoot . And almost forgot use microfiber cloths to wipe plate and film surfaces dry …. Your going to be amazed!
[/quote]

Quite right! See also https://holographyforum.org/forum/viewtopic.php?p=72268#p72268

Hey u guys update to long history these bubbles . The. Current way to do this is under water , yes i said that UNDERWATER, don’t put on the scuba gear and jump in the pool ..lol but seriously use clean filtered water, do this in at least a pretty clean environment . Put 1” of water in a darkroom tray to fit your plate , drop in clean plate ,and gently remove the backing from the pp film and slide your PP into the water , with film cut slightly smaller than your plate, align it and gently roll them both togethers. if alignment is bad,remove and reset , once aligned roll lightly, remove the PP plate and now HARD ROLL all water out. Load your plate shoot . And almost forgot use microfiber cloths to wipe plate and film surfaces dry …. Your going to be amazed!

Interesting stuff.

Well I used my last sheet of Geola film today. It's the end of my holography experience.

I'd say the most frustrating thing was trying and failing to get rid of bubbles. I built a
small laminar hood and bought a double roller and an ionizer. Initially this helped a lot
but for some unknown reason it all went pear shaped and my final set of mounted films
were pretty crap. In retrospect I should have stopped after the first run of 36. I only had
two failures with that batch and learned a lot.

The second batch all I learned was that things go wrong. I had about ten total failures and only
a half dozen nice holograms.

It is an interesting field but for me the entry barriers to doing nice work are way too high.
Film (vs photopolymer) is eyewateringly expensive. SLM lasers are very expensive even used.
And dedicating a dark, dust free space large enough to do dual beam work would mean
dropping all my other projects.

Anyhow, enough moaning. Thanks for all the help. Looking back at some of my initial questions
shows how ignorant I was and it was good to have patient help.

Cheers.

It depends on the application and the manufacturing process.

Take for example a HUD on a windscreen. When Joy (wife) was working in Luminit, in their research dept, one of her projects was to make HUDs for car windscreens. She slapped the film directly onto the windshield, and recorded it while on the windscreen itself - the entire windscreen was placed on the table.. The windshield was then placed into a car for demonstrations purposes at some conference trade show. Understand, the HOE, the hologram itself, is simply a reflective optic. A digital projector on the dashboard creates the image, which is then sent upwards to the HOE, and so into the viewer's eyes. She says that a car windscreen is composed of layers of glass and plastic sheeting. One of the layers of plastic sheeting is replaced by the hologram. It's quite possible, therefore, to embed the hologram into the windscreen during the manufacturing process, then record while the material is in the windscreen.

In another application such as VR (Virtual Reality), the idea is that you wear a pair of glasses and see "virtual information" fed to your eyes and superimposed onto the real world. Applications include the medical field and the automotive industry. In this case, there are holograms on either end of a channel called a 'diffractive waveguide'. The image, from some digital image device, is fed into an 'input hologram' at one end of the waveguide, which then sends the image along the waveguide using total internal reflection (TIR). At the other end of the waveguide is an 'output hologram' which sends the image into the viewer's eyes (https://www.uploadvr.com/content/images/2017/05/image-05.png). The holograms themselves are recorded remotely (not on the waveguide) and then inserted onto the ends of the waveguide. One of the first such VR goggles was by a Canadian company called North (Joy worked on these AR waveguides for North). North was later acquired by Google ( https://www.theverge.com/2020/6/30/21308281/google-north-focals-glasses-purchase-acquire )

Don't know. Peeling it off the original mount that replaced the cover sheet may be difficult. It's a thick volume material so keeping the film exactly as flat as it was during recording is important.

BobH,

Do they peel it before that? Or just use the original glass and a new cover piece?

Cheers.

Sandwich it in glass with optical adhesive. For example, Ceres and Zeiss are putting the material into windshields for use as head-up displays. Pictorial holograms also are best sealed, but shrinkage of the adhesive will be the issue to deal with because of the weak bond of photopolymer to substrate. Adhesive used to strengthen that bond can't affect the photopolymer and most do.

A follow-up question.

So if Geola film is used to make HOEs, (presumably for further use) how do the final
users deal with a fragile, easily scratched film that barely sticks to glass support plates?

If seen users on this forum use screen protectors to laminate the hologram but what do
commercial users do to protect such a fragile film?

Cheers.

[quote="Alan Sailer" post_id=73344 time=1734809012 user_id=11893]
I'm new to the term HOE. A quick look implies that it is a hologram used as a optical product, like a lens
rather than being used for artistic purposes.

Thanks for the reply.

Cheers.
[/quote]

HOE - Holographic Optical Elements. The idea is that you use holography to create/combine various optical components. Since glass is heavy, and working with large slabs of glass makes the product very heavy, a holographic optics can be lightweight, fast, cheap and multi-functional.

For example, one of my tasks in around 1987 was to make "laser protection goggles". The idea was that you'd make this hologram that was very, very clear in ordinary light, but the efficiency shot up 99.99% efficiency (not based on polarisation, thank god! Otherwise the function of the hologram would be useless, if the laser attacker simply changed the polarisation state of the the attack laser!). When worn in standard light, the glasses were crystal clear (there's a parameter known as the Photopic efficiency which determines how clear the glasses were.)But, when attacked with a laser, the hologram would instantly "go black", as 99.99% of the laser light would be rejected.

Over the years, they've been used for AR/VR/MR goggles, near-to-eye-displays etc .