Monolithic Integration of Plasmonic Polarizers with CMOS Microbolometers for Long-Wave Infrared Polarization Imaging

Integrating micropolarization components into bolometers not only enables infrared polarization imaging with high extinction ratios but also reduces system complexity. Here, we demonstrate on-chip microbolometers monolithically integrated with four-directional plasmonic polarizers in CMOS technology. Each polarizer comprises an Al/SiO2/Al grating structure. The plasmonic response of the polarizers enables high-fidelity polarization detection across the 7–11 μm range, yielding a maximum polarization extinction ratio (PER) and detectivity of 22.7 and 5.12 × 109 cm Hz1/2 W–1 at 9.5 μm, respectively. Using the four-directional polarization responses, we performed long-wave infrared (LWIR) polarization imaging experiments, demonstrating enhanced visibility of low-observable targets in disturbed thermal environments. This monolithic integration ensures accurate alignment with microbolometers and offers a scalable solution for industrial-grade LWIR polarization imaging.