Photon upconversion is a process by which a substance absorbs two lower eneegry photons and then emits one higher energy photon. This can be used to convert infrared light into visible light. Would it be possible to make panels that passively convert infrared into visible light, and if so which would be the best ions to use? I assume I would need a setup that goes something like:

Visible light filter, ions in solution, infrared filter.

Thoughts?

You need a nonlinear substance, and as the process is really inefficient, it's almost negligible at low intensities. You need the light to be phase-matched as well, AFAIK. Probably not going to happen much with random light sources.

 

I've only heard of this happening in nonlinear crystals. No idea what ions would work.

That's a shame. Nonetheless, thank you for an informative reply.