High performance blocking filters for the region 1 micro to 20 micro.
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 10(3) 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 micro, 5.5 micro, and 12 micro 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.
Seeley
J S
JS
Electrical Engineering Department, Queen Mary College, University of London, London, England.
Smith
S D
SD