The possibility that materials may be cooled through the interaction of electro-magnetic radiation was recognized as early as 1929. Fluorescent cooling occurs when a material absorbs radiation at one wavelength and fluoresces at a shorter wavelength. This is known as anti-stokes fluorescence. The difference is photon energy is made up of energy removed from the upper state thermal bands. Thus the material cools. Anti-stokes fluorescent cooling in solids has been demonstrated by means of atomic anti-stokes fluorescence in Yb+3 doped glass. However molecular systems--could be much more efficient than atomic systems if problems with long spontaneous lifetimes can be overcome. This can be done by means of intramolecular conversion of tautomers or by near resonance coupling of paired molecular systems. Such molecular systems could be an order of magnitude more efficient than atomic systems and the working materials fabricated at low cost.
Benefits: Development of optical cooling will allow non-refrigerant cooling of detectors and integrated circuits
