We present a simple method to determine the reflectance losses for Predictable Quantum Efficient Detector (PQED) without direct measurement of the reflectance. The ratio of photocurrents produced by the two photodiodes inside the PQED is used to determine the fractions of the s- and p- polarized components of the incident light. The reflectance of the PQED with either seven or nine internal reflections can be calculated based on the obtained polarization information for the light sources of any polarization. For the 7-reflection PQED the method allows reflectance losses to be determined with uncertainty mostly below 100 ppm (part per million) and for the 9-reflection PQED below 20 ppm in the wavelength range from 400 nm to 900 nm.
展开▼
