Reflectance and scattering properties of highly absorbing black appliques over a broadband spectral region

摘要

I present angle-dependent directional hemispherical reflectance (DHR) and bidirectional reflectance distribution function (BRDF) measurements of three highly absorbing black appliques in the 250-2000-nm broadband spectral region. DHR measurements of Energy Science Laboratories, Inc. (ESLI), Rippey, and Rodel appliques were obtained at incidence angles of 8°, 50°, and 70°. For an incidence angle of 8°, the ESLI applique exhibited the lowest DHR value of 0.3% across this entire spectral region, whereas the Rippey and Rodel had DHR values of 1.5% and 2.0-2.5%, respectively. In-plane BRDF measurements of the appliques, obtained at a wavelength of 633 nm and incidence angle of 10°, yielded Lambertian profiles from -80° to +80° with values ranging from ～10~(-3) sr~(-1) for the ESLI, 6×10~(-3) sr~(-1) for the Rippey, and 9×10~(-3) sr~(-1) for the Rodel applique. In addition, rms surface roughness and correlation lengths for the Rippey and the Rodel appliques were determined. The in-plane BRDF data were used to estimate the reflected specular component from Beckmann's scattering theory, and excellent agreement was found.