Design of polarization insensitive narrow bandpass filter

An infrared nanow bandpass filter of single half-wave cavity was designed at non-normal incidence of radiation illuminated by collimated energy within the spectral region (8-12 m). The change M the spectralcharacteristic of the filter was studied with the aid of characteristic matrix theory. Further more, needle optimization method was used to provide the best conformance to desire spectral characteristic at the operating conditions of an infrared system, thus, polarization insensitive nanow bandpass was achieved.