2
$\begingroup$

I'm currently researching ways to get the human perceived colors red, green and blue when you only have a mostly blue spectrum available at your source (using electroluminescence). The solution should be quite simple so that an engineer can build this without needing a laboratory.

Simple color filters filter every frequency but one frequency range, so the light gets darker. So this is not very feasible to use this.

However then I found this quote on wikipedia:

high luminance inorganic blue phosphor is used in combination with special color conversion materials

So there seem to exist materials which red shift blue light by passing the light though (?) these materials. Do such materials exist?

According to this answer (Is it possible for a material to shift the frequency of all light reflected off of it by a specific and constant value) only one technique was named (Raman scattering) which is again not practical feasible to use.

$\endgroup$
  • $\begingroup$ What about using phosphors? I'm pretty sure you can find Day-Glo colors that will glow green or red under blue light. $\endgroup$ – Solomon Slow Jul 19 '16 at 22:49
2
$\begingroup$

you are basically looking for fluorescent materials. These materials are coated inside the fluorescent lamps which absorb the ultraviolet light and convert it into visible line radiations. Rare earth compounds such as Gadolinium oxy sulphate are (were ?) very commonly used phosphors. However new research is going on you may find this article interesting.

The process of color conversion inside the phosphor can be understood as, when a high energy photon (blue or UV) falls on the phosphor the atoms inside the phosphor excites into higher energy levels. These atoms are then de-excited through several routes and emit photons of smaller energy.

This is not exactly frequency shift of light but rather absorption and emission.

I hope this will help,

$\endgroup$
2
$\begingroup$

There is likely no practical and straightforward way to do what you want.

An acousto-optic modulator can shift an optical frequency by a fixed amount, but the amount of the shift is small, not big enough to cause a difference of color perception. It is also not particularly efficient; typically a few percent of the energy in the input beam is converted to the new wavelength and the majority passes through without changing.

A phosphor can generate a large color shift, but the output color is basically fixed; it depends on the band or orbital structure of the phosphor chemical, not on the color of the input (charging or pumping) light.

$\endgroup$
  • $\begingroup$ could you please elaborate more on the phosphor color shift? That the shift is fixed is no problem. In the field of electroluminescence it seems that ZnS:Mn is called a Phosphor in this context. So I want to avoid any term uncertainty. $\endgroup$ – Benedikt S. Vogler Jul 19 '16 at 19:11
  • $\begingroup$ The shift is not fixed, the output wavelength is fixed. $\endgroup$ – The Photon Jul 19 '16 at 19:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.