Oh my gosh, when I was a child I remember going into a shop at the beach which sold all kinds of holographic images. And I remember a couple of them had pictures of things like a telescope or binoculars, and you could actually look into them! I’ve been searching for a while for any kind of information about these things, and I was almost ready to believe that I had just imagined it. But there is the same thing just 1 minute into this video!

Hmm.

You’d think that you could take three exposures, using a red, blue, and green laser, and then use optics to recombine the output to create a color hologram.

But I’ve never heard of such a thing. I wonder if there’s some kind of physical limitation that I can’t think of preventing it?

kagis

Nope. Apparently you can do exactly that, and devices do exist to do it:

https://www.litiholo.com/hologram-kits-color.html

First I’d seen of this, though.

EDIT: Ah, late in the video, they actually do show a few color holograms, the most-obvious of which is probably the R2D2 shot, which clearly has both blue and red.

What sorcery are these?

Magnets.