Method for realizing a primary photometric standard of optical radiation using a photodetector and photodetecting apparatus therefor

摘要

In a first method for realizing a photometric standard based on a responsivity for a photometric quantity, there is measured an output current from a photodetector of a photometric standard photodetecting apparatus by projecting monochromatic lights having predetermined radiation illuminances at respective wavelengths within the visible region onto the photodetector, both through an optical filter for the spectral luminous efficacy and directly without the optical filter. A responsivity of the photometric standard photodetecting apparatus is calculated by measuring an apparent spectral transmittance of the optical filter from the measured output current. In a second method for realizing a photometric standard, there is measured an output current outputted from a photodetector of a photometric standard photodetecting apparatus by projecting a beam of light from a light source having a predetermined relative spectral distribution onto the photodetector, both through the optical filter and directly without the optical filter. A responsivity of the photometric standard photodetecting apparatus is calculated from the measured output currents without measuring the spectral transmittance of the optical filter.