Optical power and transmittance measurements and their use in detector-based realization of the luminous intensity scale

Abstract

Responsivity calibrations of trap detectors with a cryogenic absolute radiometer and a power-stabilized 543.51 6-nm He-Ne laser are described. The trap detectors are used as transfer standards of optical power at visible wavelengths because they have a predictable spectral responsivity. New results on transmittance measurements of PRC Krochmann <i>V</i>(λ) filters are presented, especially the angle and temperature dependence of the transmittance. The characterized trap detector and the <i>V</i>(λ) filter are used for a novel realization of the SI base unit of luminous intensity, the candela. Test measurements indicate a good agreement with previous photometric scales.