MEMS-based Low SWaP Solutions for Multi/Hyperspectral Infrared Sensing and Imaging

We present a MEMS tunable Fabry-Perot filter platform for multi- and hyper-spectral sensing and imaging across the SWIR, MWIR or LWIR wavelength bands. The technology employs surface micromachined, tensile silicon membranes to create a movable distributed Bragg reflector (DBR) as part of a Fabry-Perot structure. Fabricated 1 mm-dimension broad band SWIR filters are demonstrated with a wavelength tuning range of 1.77–2.42 μm. These millimetre-scale tunable filters show excellent surface flatness in the order of 15 nm, and excellent optical uniformity, with a transmission peak wavelength variability of 5% across the entire optical tuning range. We also demonstrate narrow-band Fabry-Perot filters suitable for hyperspectral sensing and/or imaging, using air as the low-index medium in the movable DBR to improve reflectivity. These filters are also demonstrated in the SWIR wavelength range, and achieve narrow spectral linewidths of δλ/λ c < 2%.