Synthesis of narrow-band interference filters with absorbing metal films

摘要

Designs of narrow-band infrared metal-dielectric interference filters are proposed. The unique feature of the developed filters is the fact that the metal films are positioned within the interference coating structure to suppress the unwanted transmission of long-wavelength radiation with wavelengths exceeding 3.5 mu m. The peculiarities of the design and spectral properties of such filters are demonstrated using a narrow-band filter with a transmission maxi- mum at 3.43 mu m, which is used in infrared nondispersive absorption gas sensors. (C) 2021 Optical Publishing Group