Precision nickel printing screens are shown to be very useful as far infrared bandpass filters. For a range of such regularlyperforated screens, transmission maxima have been observed to lie at frequencies between 58 cm-1 and 142 cm-1. In general,the peak of transmission is measured to be over 0.9. It is found that this high transmission is little degraded by cascadingseveral screens, but the overall filter Q value may be increased from about 2 to a value of about 6.
P. G. Huggard, P. G. Huggard,
"Rugged far infrared bandpass filters", Proc. SPIE 2104, 18th International Conference on Infrared and Millimeter Waves, 21044Y (30 August 1993); doi: 10.1117/12.2298610; https://doi.org/10.1117/12.2298610