IR laser deflourescenating?

Read this http://www.repairfaq.org/sam/laserioi.htm#ioildls
Go to alt.lasers and ask also
http://groups.google.com/group/alt.lasers?lnk=gschg&hl=en

Any shorter wavelength of light will charge something the phosphoresces (ie glows in the dark). Violet will charge all other visible colors, green will charge yellow and up in wavelength, red would only charge up darker shades of red. The wavelength of the light doing the charging must be shorter than the wavelength of light emitted by the fluorescing/phosphorescing object (shorter wavelength is higher energy).

The "de-phosphorescing" being talked about here is what Benm is talking about. Sometimes lower energy light can provide the activation energy necessary for a non-radiative pathway. If left alone, the electrons that are at higher energy will sit there for a while and eventually fall back down to ground radiatively (emitting a photon). But there are other ways for electrons to give up their energy, such as non-radiative recombination. The IR or red light isn't high enough energy to cause electrons to excite up to the high-energy state, but it can provide the activation energy for high-energy electrons to transition back down in energy must faster than they otherwise would have through non-radiative processes.

And that is probably why IR lasers only work sometimes. There has to be an energy level the electrons can go to with the energy provided by the IR light. If no such level exists or the transition is forbidden, it's not likely to work.

With the usual greenish-glow-in-the-dark materials, red lasers seem very effective in removing electrons from the forbidden-locked charged state.

One interesting application that uses the reverse effect are IR indicator cards that are pre-charged: IR light pushes the electrons further, allowing a radiating transition at visible energy levels, resulting in a spot of light wherever IR light hits the card.

That's probably also why it gets a lot brighter, and then darker. It just speeds up the glowing process... It sounds like it doesn't work with many glow in the dark things. Mabye I could sell this star for hundreds on Ebay!

Hello All,

I also have noticed this with some glow-in-the-dark stars I've got. The effect is quite remarkable. (enough that I can 'negatively' write on them with my long open-can...) The red light instantly drains the material!

cheers,
kernelpanic

I was wrong, the red also discharges. I was fooled when it lit up really bright, right before it went down. The red was so bright I couldn't see anything.