Spectral Power and Irradiance Responsivity Calibration of InSb Working-Standard Radiometers.

New, improved-performance InSb power-irradiance meters have been developed and characterized to maintain the National Institute of Standards and Technology (NIST) spectral responsivity scale between 2 and 5.1 mum. The InSb radiometers were calibrated against the transfer-standard cryogenic bolometer that is tied to the primary-standard cryogenic radiometer of the NIST. The InSb radiometers serve as easy-to-use working standards for routine spectral power and irradiance responsivity calibrations. The spectral irradiance responsivities were derived from the spectral power responsivities by use of the measured area of the apertures in front of the InSb detectors.