Angle of incidence independent metamaterial for hyperspectral imaging

An angle-insensitive metamaterial spectral filter (MS) that demonstrates great potential as a spectral disperser within hyperspectral imaging (HSI) was simulated and analyzed. The innovation of the MS is its operation on the principle of coupled resonances, whereby coupling the classical narrowband Fabry-Perot (FP) resonance and a broadband cavity mode (CM) resonance can tune its dispersive spectral behavior. This results in the MS transmitting a narrow passband within a broad stopband for a focused light cone. Compared to conventional methods, this novel approach has the potential to reduce the size, weight, and power (SWaP) of a HSI system. Currently, hyperspectral sensors require bulky dispersion controlling optics to collimate the incoming beam due to physical limitations set forth by the disperser. Because the disperser is usually a transmission/reflection grating, the angle of the incident beam significantly impacts whether the correct wavelength is incident on the sensor. At even a slightly off-normal (AoI), the beam could either miss the sensor entirely, or create cross talk between adjacent pixels. This fundamental limitation produces difficulties in managing obliquely incident light, hence the need for collimation. To get around this, the AoI insensitive metamaterial will be used in the place of the disperser and collimated optics to properly deliver obliquely incident light to the detector. When applied correctly, the MS can be used within a remote sensing detector to provide high performance spectroscopy that is similar to larger heritage sensors.