A germanium-immersed thermistor bolometer infrared detector is described which utilizes cone-channel condenser techniques to supplement in one meridian the optical gain afforded by conventional immersion lens techniques in the presence of asymmetrical pupils such as the rectangular exit slit of a spectrometer. Data are presented describing its construction, properties, and installation at the spectral focal plane of an experimental spectrometer.
Marc G. Dreyfus, "Wedge-Immersed Thermistor Bolometer," Appl. Opt. 1, 615-619 (1962)