ABSTRACT
A quantum well infrared photodetector which converts long-wavelength infrared radiation into short-wavelength infrared (or visible) radiation is proposed and physics of its operation is considered. The quantum well infrared photodetector utilizes an intraband absorption of radiation in a quantum well in the emitter and interband emission in either classical or quantum well in the collector. It is shown that the efficiency of energy conversion of long-wavelength radiation into short-wavelength radiation can be about unity.
