Computer-generated holography with ordinary display

btbuildem wrote: post #5

> We demonstrate three-dimensional color image reproduction using a two-layered hologram cascade composed of an iPhone and a spatial light modulator. So, not just an ordinary display then? What does this "spatial light modulator" look like?

In this application, it would probably look like a transparent liquid crystal display on top of the phone. Usually LCDs are modulating the polarity of light, and you have polarizing filters before and after so that the modulation of polarity results in modulation of intensity; but I've read about other ways to arrange the LCD such that you modulate the phase of the light passing through instead, that's what you need for holography (although I thought you needed a coherent light source)

Here's a commercially available SLM based on reflective Liquid Crystal on Silicon (similar to what you might find in an LCD projector), that actually has listed prices: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10... No endorsement, just an early search result.

Re: Computer-generated holography with ordinary display

#9

Post by Animats » Mon, Apr 15, 2024, 6:42 AM UTC

btbuildem wrote: post #5

> We demonstrate three-dimensional color image reproduction using a two-layered hologram cascade composed of an iPhone and a spatial light modulator. So, not just an ordinary display then? What does this "spatial light modulator" look like?

Probably like this.[1]

It's a variant on a liquid crystal display, set up to adjust phase, rather than intensity. Clever. Price around US$13,000 and up.

[1] https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...

Re: Computer-generated holography with ordinary display

#10

Post by hellonull » Mon, Apr 15, 2024, 7:55 AM UTC

Animats wrote: post #9

btbuildem wrote: post #5

> We demonstrate three-dimensional color image reproduction using a two-layered hologram cascade composed of an iPhone and a spatial light modulator. So, not just an ordinary display then? What does this "spatial light modulator" look like?

Probably like this.[1] It's a variant on a liquid crystal display, set up to adjust phase, rather than intensity. Clever. Price around US$13,000 and up. [1] https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...

That is lab equipment, of course it’s going to be horrendously expensively. Look how much a pack of bolts costs.