A newly developed pyrolytic graphite polarizer foil has been found to provide a reasonably high transmittance and an excellent degree of polarization in the total spectral range above 10µ. Its use has certain advantages over other types of polarizers for such wavelengths.
G. RUPPRECHT, D. M. GINSBERG, and J. D. LESLIE, "Pyrolytic Graphite Transmission Polarizer for Infrared Radiation," J. Opt. Soc. Am. 52, 665-668 (1962)