Fabry-Perot Double-Cavity Optically Controlled Narrow Tunable Bandpass Filter

Spectral detection and recognition employing optical filter is an important tool for NASA?s mission on studying atmospheric and surface parameters and analyzing/monitor global environment changes. It can acquire information of biology and biogeochemistry of ecosystems, global carbon cycle, global water and energy cycle, atmospheric chemistry, and natural hazards. It is particularly important that the optical filter should be narrow passband, high transmission, high out-of-band rejection, accurate tuning, large tuning range, relatively wide field of view, and large aperture. Developing extremely narrow bandwidth (sub-angstrom) tunable filters can improve measurement capability of ground-based or airborne/space-borne remote sensing systems and can benefit terrestrial and space based LIDAR for weather sensing. New Span Opto-Technology Inc. proposes herein a new all-optical controlled Fabry-Perot double-cavity filter. The cavity structure of the filter is specially designed to simultaneously achieve narrow bandpass and large free spectral range. Highly control-light sensitive photochromic material as tuning medium makes all-optical control tuning practical and attractive. Phase I will demonstrate the feasibility of the proposed all-optical controlled double-cavity filter. Phase II will optimize the device design, fabrication, and result in a compact packaged tunable optical filter for NASA and commercial applications.