REALIZATION OF A SCALE OF ABSOLUTE SPECTRAL RESPONSE USING THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY HIGH-ACCURACY CRYOGENIC RADIOMETER

Using the National Institute of Standards and Technology high-accuracy cryogenic radiometer (HACR), we have realized a scale of absolute spe ctral response between 406 and 920 nm. The HACR, an electrical-substit ution radiometer operating at cryogenic temperatures, achieves a combi ned relative standard uncertainty of 0.021%. Silicon photodiode light- trapping detectors were calibrated against the HACR with a typical rel ative standard uncertainty of 0.03% at nine laser wavelengths between 406 and 920 nm. Modeling of the quantum efficiency of these detectors yields their responsivity throughout this range with comparable accura cy.