Fluorescent refrigeration
AssigneeThe Regents of the University of California
InventorsRichard I. Epstein, Bradley C. Edwards, Melvin I. Buchwald, Timothy R. Gosnell
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Abstract
Fluorescent refrigeration is based on selective radiative pumping, using substantially monochromatic radiation, of quantum excitations which are then endothermically redistributed to higher energies. Ultimately, the populated energy levels radiatively deexcite emitting, on the average, more radiant energy than was initially absorbed. The material utilized to accomplish the cooling must have dimensions such that the exciting radiation is strongly absorbed, but the fluorescence may exit the material through a significantly smaller optical pathlength. Optical fibers and mirrored glasses and crystals provide this requirement.
Claims14
An apparatus for removing heat from an object to be cooled, which comprises in combination:
- a. means for generating substantially monochromatic electromagnetic energy;
- b. a working material having atoms with energy levels such that at most a small number of energy levels in an excited state thereof are directly excited by the substantially monochromatic electromagnetic energy from the ground energy level of the atoms, such that the levels in the excited state which are not directly excited have an energy spacing such that they may be thermally redistributed, and such that fluorescence to the ground state can preferentially occur from the thermally equilibrated energy levels, whereby the average photon energy for fluorescence to the ground energy level is greater than the energy of the substantially monochromatic electromagnetic energy;
- c. means for directing the substantially monochromatic electromagnetic energy through said working material such that the optical pathlength of the substantially monochromatic electromagnetic radiation is large compared with the optical pathlength for the fluorescence in said working material;
- d. means for bringing the object to be cooled into thermal contact with said working material;
- and
- e. means for thermally isolating the object to be cooled and said working material from external radiative heat sources.
Dependencies are inferred from the claim text.