By cooling the chopping blade, the recovery time of a thermal detector can be reduced to a negligible fraction of the chopping cycle. The possible gains in chopping frequency and responsivity are analyzed and calculated for the case of square-wave chopping. Disadvantages, such as distortion of the detector output waveform, are also analyzed.
E. SPEYER and E. BRIGMANIS, "Forced Cycled Cooling of Thermal Detectors," J. Opt. Soc. Am. 51, 1417-1421 (1961)