TITLE: Is there a material that could "convert" near infrared frequency to infrared?
QUESTION [1 upvotes]: 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,

REPLY [1 votes]: 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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