Low-loss high-Q optical bandstop filter based on chalcogenide glass grating structures

We have proposed to make use of the low-loss characteristic of chalcogenide glass material for infrared filter applications. A stop-band chalcogenide filter design based on a grating structure was presented. The study shows that by varying the grating's geometric structure, the bandwidth can be adjusted and the resonant frequency can be fine-tuned. However, high-Q characteristics can only be realized with thicker grating structures. This initial investigation indicates that a chalcogenide glass stop-band filter can achieve reflectances higher than 90% at infrared wavelengths.