Measurement of infrared multilayer filters at temperatures down to 4 deg K
J S Seeley, R Hunneman, A Whatley
SPIE Proceedings, 325, Pages 180-183 (1982)
Measurement is reported at 4 deg K (and blocked transmission below 10-5) of PbTe/ZnS thin-film filters deposited on Ge substrates. The reduced carrier-absorption which is obtained by cooling these PbTe films is found to accord with simple theory. Advantage for various high-performance multilayers by cooling is significant at the longer wavelengths, and has been verified.