Far infrared filters for the GALILEO-Jupiter and other missions
J S Seeley, R Hunneman, A Whatley
Applied Optics, Vol 20, No 1, Pages 31-39 (1981)
Extrapolation of PbTe/II-VI multilayer interference-filter technique from 20 to beyond 40µm is described and PbTe transparency reviewed; improvements below 20µm are reported. A composite filter cutting on steeply at 40µm is described that uses absorptive films of ZnS and As2S3, thin Quartz, and supplementary multilayer interference. Absorptive filters are described containing the II-VI compounds since these are found transparent at wavelengths shorter and longer than their reststrahl.