Abstract
Integrated polarization focal plane detection imaging has the advantages of small size, high system integration, high mechanical stability and real-time polarization imaging in multiple polarization directions. We have developed a simulation model for back-illuminated mid-wave InAs/GaSb Type-II superlattices (T2SLs) infrared focal plane arrays (FPAs) on-chip integrated polarization grating. The polarization grating is an Al-ZnS double-layer subwavelength grating with antireflection coating, which has a better polarization transmission than a single-layer Al grating with the same deep slot. The effect of different grating parameters on the detector is simulated and optimized by the finite-difference time-domain (FDTD) method, and the results obtained are qualitatively interpreted in a physical sense by the Fabry-Perot-like (F-P-like) resonance theory. The optimized grating has a TM polarization transmittance higher than 92% and extinction ratios greater than 32 dB for wavelengths from 3-5 μm, and is suitable for infrared polarization imaging in the 0°-50° field-of-view range. The simulation results can provide theoretical basis and guidance for the design of polarization gratings for mid-infrared monolithic integrated polarization InAs/GaSb T2SLs FPAs.
Published Version
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