Tunable Far‐Infrared Polarization Imaging Based on VO₂ Metasurfaces

Abstract

Polarization imaging enables the capture of material properties and surface characteristics of objects, finding applications in remote sensing and defense. However, most existing polarization imaging systems rely on polarization filtering elements, resulting in energy loss exceeding 50% and compromising intensity imaging performance. Conventionally, a rotary device equipped with different polarizers and a blank area is used to acquire both polarization and intensity images, which is cumbersome for integration and miniaturization purposes. In this study, a miniaturized and easily integrated active metasurface based on VO2 grating structure for switchable detection of intensity and polarization in the far‐infrared band (8–14 µm) is proposed. With VO2 in the dielectric state, the device exhibits high transmittance for both TE‐ and TM‐polarized light (Experimental transmittance of up to 65%). Upon phase transition to the metallic state, the device demonstrates low transmittance for TE‐polarized light while maintaining high transmittance for TM‐polarized light (linear polarization extinction ratio up to 10 dB). Finally, the tunable thermal intensity and polarization imaging capabilities of the custom‐made setup are characterized. The metasurface showcases comparable performance to standard commercial polarizers in terms of polarization imaging. The developed tunable far‐infrared polarization imaging system holds promise for next‐generation multidimensional information perception.