An absolute cryogenic radiometer for laser calibration and characterization of photodetectors

Abstract

Absolute cryogenic electrical-substitution radiometers (ESRs) are widely used in many applications of absolute radiometry and are accepted today as being the most accurate instruments for radiant-power measurements. An absolute cryogenic electrical-substitution radiometer has been developed at the All-Russian Research Institute for Optophysical Measurements (VNIIOFI) as the radiometric standard of Russia. The design and characterization of the VNIIOFI absolute cryogenic radiometer currently used for the calibration of detectors in Russia is described. This radiometer uses laser radiation and a power level of 1,3 mW and achieves an uncertainty of 0,02%. The factors limiting the overall uncertainty of the VNIIOFI cryogenic radiometer are also analysed.