抄録
In this study, we tried to measure spectral hemispherical transmittance of piling quartz glass plates with double-layer anti-reflection (AR) coatings in order to verify the spectral control performance for diffuse irradiation. It was revealed that spectral normal transmittance of the filter was reduced with increase in the number of the plates except for the specific narrow wavelength region, where the AR coatings worked ideally. As a result, it was shown that the filter achieved effective spectral control in normal direction for the diffuse irradiation although the coatings were designed for irradiation with polar angle of 45 degree.
