Optical Characterization of Absorbing Coatings for Sub-millimeter Radiation

Experimental results are presented on the specular and diffuse reflectance (BRDF) of a variety of surfaces that can be used to absorb sub-millimeter radiation. Although the emphasis of this study is on the development and optical characterization of black absorbing coatings, intended for use in the spectrometers aboard the FIRST satellite, also some convenient materials for laboratory use are discussed. The here presented data have been collected room temperature Introduction. The optical properties of the coatings have been studied in the 0.1 0.9 mm wavelength region in order to comply with the wavelength bands covered by the HIFI and PACS spectrometers. Optical characterization has been performed using monochromatic light at selected wavelengths across the 100-900 micron wavelength region. (96.5μm, 118.8μm, 184.3μm, 496μm and 889μm) created by an optically pumped far-infrared laser.