I have a laser with a wavelength of 650 nm (visible red light) and was wondering if there is some sort of material that could be used to absorb and disperse a different frequency of light around (900 nm).

Energy would just be dissipated by the material as it is converted to a lower frequency,

  • $\begingroup$ I just thought that it possible to red-shift but that would take a far enough distance, so that solution is impractical. $\endgroup$
    – AlanZ2223
    Dec 21, 2014 at 5:23
  • $\begingroup$ You realize of course that any absorptive material will do that through black body radiation but it will be a dispersed spectrum? You want a coherent beam out of this, or at least a beam? rp-photonics.com/frequency_doubling.html for doubling frequency exists, not for halving though . $\endgroup$
    – anna v
    Dec 21, 2014 at 5:39
  • $\begingroup$ Yes I am looking for a directed beam. It should proceed like this: I take a red laser and direct it at the material and on another end a beam or one with little divergence is dispersed $\endgroup$
    – AlanZ2223
    Dec 21, 2014 at 6:32
  • $\begingroup$ What you are looking for is another laser. A converting material will not do. $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 7:39
  • $\begingroup$ Check out "CARS" and "CSRS" -- Stokes formalism for mixing wavelengths in a nonlinear material to generate sum/difference wavelengths. $\endgroup$ Dec 21, 2014 at 13:17

2 Answers 2


I found a link for halving too:

Nonclassical light generation in the process of self-frequency halving in a periodically poled active nonlinear Nd:Mg:LiNbO3 crystal

Nonclassical light generation at self-frequency halving in periodically poled active nonlinear crystals is studied. The squeezing spectra of fundamental radiation and its subharmonic are investigated for a periodically poled Nd:Mg:LiNbO3 crystal.

It seems to be a matter of research at the present time, not something available for any laser beam in the manner you envisage.


Assuming when you say the output is "dispersed" you mean it is incoherent and radiating in all directions, what you are asking for is a fluorescent material.

A Google search for "IR fluorescence" finds a couple of companies making these materials for biological sample marking, however the ones I checked into further need a slightly longer excitation wavelength to work efficiently.

If you actually want a coherent output beam, these or similar materials might be usable as the active medium in a dye laser to be pumped by your 650 nm beam.


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