The paper: https://preprints.opticaopen.org/articles/preprint/Computer-...

> 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.

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.

Yes, but you get lab snacks :)

alls I know is the nintendo 3DS could do this on the cheap

An actual holographic article, not some autostereoscopic or barrier! Thanks for the find!

CGH: Computer-generated holography: https://en.wikipedia.org/wiki/Computer-generated_holography