The extent to which the thermal capacitance and resistance of a black coating on a pyroelectric detector offset the gain in optical absorptance is investigated. A black paint is shown to be of little value, but a coating of gold-black may increase the detector responsivity for modulation frequencies up to at least several kilohertz. When a coated pyroelectric detector is calibrated electrically, a correction is necessary for the thermal impedance of the black. For gold-blacks of superficial density 2 g m-2, this correction is shown to be less than 2% for frequencies within the 0–100-Hz range.
W. R. Blevin and Jon Geist, "Influence of Black Coatings on Pyroelectric Detectors," Appl. Opt. 13, 1171-1178 (1974)