Detector, linear cooled bolometer

If the interferometer mirror speed is such that the optical velocity is 0.316 cm s (HeNe laser frequency of 5 kHz), 4000-cm radiation is modulated at 1.25 kHz (see Eq. 2.11). Thus, the response time of a detector for FT-IR spectrometry must be less than 1 ms. Although several cryogenically cooled detectors have response times this low, the only mid-infrared detectors that have an appropriate combination of high speed, reasonably good sensitivity, low cost, good linearity, and operation at or near room temperature are the pyroelectric bolometers. 

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