Compact Hyperspectral Imager Using Tunable Metasurfaces

To meet the size, weight, and power consumption (SWaP) constraints imposed by small mobile platforms, Nanohmics Inc. proposes to develop a battery-operated, low-SWaP hyperspectral imaging (HSI) system by combining a metasurface-based tunable spectral filter with a commercial off-the-shelf COTS long-wavelength infrared (LWIR) imager.  This low-SWaP system will achieve high spatial resolution, fit aboard small mobile platforms, and be capable of detecting targets and threats in cluttered environments.  The key enabling technology for the proposed HSI is an electronically tunable spectral notch filter microfabricated using ultrathin patterned graphene optical metasurfaces.  The tunable filter is thin enough to be integrated directly into a COTS LWIR camera. The proposed compact LWIR HSI system will be electronically switchable between two image collection modes: (1) high-frame rate broadband imaging, and (2) hyperspectral imaging with high spectral resolution.  In broadband mode, the filter is switched off and the imager operates as a conventional LWIR or thermal camera.  In hyperspectral mode, the tunable notch filter scans through the LWIR spectral producing a spatial-spectral data cube with full focal plane array (FPA) resolution.  In Phase I, Nanohmics will demonstrate the feasibility of a compact LWIR dual-mode hyperspectral imager based on tunable optical metasurfaces by designing, fabricating, and testing a proof-of-principle imager, achieving TRL 3.    The team will identify the hardware requirements for a prototype that achieves all performance objectives, and perform a trade study of different COTS FPA sensors and focusing optics, including engineering and ray trace studies to identify performance limitations.  Modeling and simulation will predict system performance and help to optimize prototype design.  In Phase II, Nanohmics will build and test the dual-mode imager prototype to achieve TRL 4.  Use of COTS components and standard microfabrication methods will reduce costs and provide a rapid route to commercialization.