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

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 degrees, 50 degrees, and 70 degrees, For an incidence angle of 8 degrees, 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 degrees, yielded Lambertian profiles from -80 degrees to +80 degrees with values ranging from 10 (3)sr(-1) for the ESLI, 6 X 10 (3)sr(-1) for the Rippey, and 9 X 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. (C) 2001 Optical Society of America.