How do you convert an LED infrared light source into visible light?

You might try the sci.optics newsgroup. They jaw about stuff like this all the time. They are heavy on the science.

Al

You don't! IR photons have less energy than visible photons. Thus, in ordinary luminescence, the luminescence will always be at a lower frequency (longer wavelength) than the exciting radiation. In principle, there are nonlinear techniques usually using parametric processes that will allow IR to CONTROL the generation of visible light. Doing so requires extra energy as well as relatively complicated methods.

Bill

-- Fermez le Bush

Radio Shack used to sell a little card that would glow red when held in the IR beam of a remote. Edmund scientific may sell this material now. John

Didn't you have to "charge" the card first by exposing it to UV light?

The IR light would "trip" electrons/holes that were boosted to a higher state and cause then to fall to some intermediate state and emitting a photon in the visible light range.

No, I have one of the cards. It lights up pretty much instantly when exposed to infrared light (such as from a remote control). It tells the technician that the IR diode is producing at least some IR energy.

Maybe you are thinking of those glow in the dark devices or coating materials, which, as far as I know, charge up under visible light.

I've never seen one of these that worked well (stayed on and glowing all night after a full charge). When I was a kid, radioactive Radium glow-in-the-dark watches were common. They would glow in complete darkness but they supposedly killed a lot of workers in the manufacturing plant.

What I am looking for is the mineral or rare-earch material that will light up in the presence of infrared. Something commonly available would be nice, but it seems to be a trade secret.

Beachcomber