Measurements of Diamond Turned Copper Mirrors at Glancing Incidence

摘要

The results of glancing incidence absorptance measurements performed on diamond turned copper mirrors are presented. A photoacoustic calorimetry technique is used in which the output from a low power, chopped cw Nd:YAG laser (1.06 mu m) is incident upon the mirror at angles of incidence from 0 to 87 deg, for both s and p-polarizations. Measurements are obtained as a function of the diamond turning groove orientation with respect to the plane of incidence. Minimum absorptance at high angles of incidence is achieved with s-polarized light and with the grooves aligned parallel to the plane of incidence. The effects on the absorptance of a large scratch at glancing incidence are also described. (ERA citation 12:044742)