Calibration of the reflectance of hard targets for a coherent Doppler lidar

Data on the bihemispherical and directional-hemispherical reflectance were measured on a gold standard, a flowers of sulfur secondary standard, glass bead blasted aluminum, and 120 grade aluminum oxide sandpaper. These reflectances were measured for the P(24) and P(20) 10-microm and R(26), R(20), and P(20) 9-microm CO(2) lines. The specular and retroreflection character of scattering from aluminum and sandpaper was evident in our measurements. Our results agree reasonably well with previous measurements. Also when the sphere is irradiated with polarized light no difference was noted in the reflectance, which indicates that the integrating sphere is a depolarizer.