High performance blocking filters for the region 1µm to 20µm

Seeley, J. S. and Smith, S. D. (1966) High performance blocking filters for the region 1µm to 20µm. Applied Optics, 5 (1). pp. 81-85. ISSN 0003-6935 doi: 10.1364/AO.5.000081

Abstract/Summary

A set of filters based on the sequence of semiconductor edges is described which offers continuity of short-wave infrared blocking. The rejection throughout the stop region is greater than 103 for each filter and the transmission better than 70% through one octave with a square cutoff. The cutoff points are located at intervals of about two-thirds of an octave. Filters at 2.6 ,µm, 5.5 µm, and 12 µm which use a low-passing multilayer in combination with a semiconductor absorption edge are described in detail. The design of multilayers for optimum performance is discussed by analogy with the synthesis of electric circuit filters.