Metamaterial-Based FP Filter for Hyperspectral Imaging in Cubesat Applications

This work introduces a metamaterial-based Fabry-Pérot (FP) filter for hyperspectral imaging (HSI). A planar DBR-metasurfaceDBR structure is designed for mid-wave infrared (MWIR) applications with sub-wavelength silicon (Si) gratings for tuning resonance wavelengths through variations in the duty cycle. The generalized metamaterial spectral (MMS) structure can be applied in various infrared spectral ranges by using the right materials and rescaling the size. Each DBR contains four pairs of quarter-wavelength stacks of silicon dioxide (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiO}_{2}$</tex>) and Amorphous Silicon (a-Si). The resonance wavelength is accurately controlled by adjusting the dimensions of nanoposts, which will provide efficient, high-performance infrared filtering in a compact, lithography-friendly design. The structure has achieved 99 % transmission at a wavelength of 4279 nm in TE mode, with high Qfactor and maximum transmission up to 95 % at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta=40^{\circ}$</tex>. Because of its planar nature, it can be fabricated in just one binary lithography step. This reduces manufacturing complexity. The proposed hyperspectral metamaterial-based sensor may have potential commercial applications in environmental monitoring form CubeSat, antiterrorism, medical diagnostics, forensic analysis, and food safety.