Characterization of the Reflectance Distribution Function of Low Reflectivity Surfaces in the Infrared Region

The reflectance distribution function describes optical properties of opaque materials, particularly the specular, the glossy, and the diffuse Lambertian reflectance. Aeroglaze Z302 absorptive polyurethane paint is the coating of choice for optical instruments. While the material is widely used in many applications, the reflectance as well as performance of the coating surface have not been characterized, especially with the infrared region. Bidirectional reflectance measurements have already been taken at wavelengths of 633, 850, 4500, and 10600 nm. By employing directional scatter analysis to the experimental data, we have provided a simulation for the bidirectional reflectance property of the coating surface. The results provide further information about the possible impact of stray light on the performance of optical instruments.