Patent ID: 7501627

Claim:
An infrared sensor that generates an electrical signal output by converting infrared radiation into shorter wavelength light, comprising: an input apparatus receiving infrared incoming radiation and directing the incoming radiation on a path into a wavelength multiplexer; a laser pump generating a laser beam of a wavelength shorter than the incoming radiation; beam directing apparatus directing the laser beam into the wavelength multiplexer on a path that is identical to and overlaps the path of the incoming radiation; a thermoelectric cooler interconnected with and maintaining the laser pump at a stable temperature and the laser beam at a stable wavelength; an upconversion crystal coupled with the wavelength multiplexer and receiving the overlapping laser beam and incoming radiation from the wavelength multiplexer and combining the laser beam and the incoming radiation into an output light beam of shorter wavelength than the laser beam; and a photodetector to which the output light beam is directed and which converts the output light beam into an electrical signal, the amplitude of which is dependent upon the intensity of the infrared incoming radiation.