Effect of surface roughness and complex indices of refraction on polarized thermal emission.
We present a series of measurements characterizing the dependence of polarized thermal emission on surface roughness. In particular, we measure the spectrally resolved degree of linear polarization (DOLP) for a series of roughened borosilicate (Pyrex) glass substrates as a function of the roughness parameter Ra, the root-mean-square slope distribution, and observation angle theta. Also measured are a series of smooth glass substrates coated with two particular polymers of interest, i.e., a common commercially available Krylon paint and a chemical-agent-resistant coating paint. The DOLP is measured over a 4-13 microm wave band by using a modified Fourier transform IR spectrometer in which a wire-grid polarizer and a quarter-wave Fresnel rhomb are used in conjunction to measure all four Stokes parameters. In addition, we show an enhanced DOLP due to anomalous dispersion exhibited by the surface material.
Gurton
Kristan P
KP
U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783-1145, USA. kgurton@arl.army.mil
Dahmani
Rachid
R