Characterization of bidirectional transmissive and reflective properties of black silicon

This paper describes the initial work of characterizing the transmissive and reflective properties of Black Silicon (Si) diffusers. The diffusers are 100mm diameter black silicon samples fabricated at Goddard Space Flight Center (GSFC). The 8° Directional Hemispherical Reflectance (DHR) from 250nm to 20 microns and the Bidirectional Reflectance Distribution Function (BRDF) and Bidirectional Transmissive Distribution Function (BTDF) of a Black Si sample were measured at 632.8nm, 1064nm, and 1550nm using the GSFC Code 618 Radiometric Calibration Laboratory’s (RCL)’s optical scatterometer. The diffuser exhibits extremely low specular reflection up to ~1100nm. There is no evidence of retroscatter. The measurements are traceable to those made at the National Institute of Standards and Technology (NIST).