Broadband Single‐Chip Full Stokes Polarization‐Spectral Imaging Based on All‐Dielectric Spatial Multiplexing Metalens

Abstract Compared with intensity imaging, more inherent information of objects can be obtained by polarization and multispectral imaging. Here, a broadband and highly integrated single‐chip full Stokes polarization‐spectral (FSPS) imaging is demonstrated using all‐dielectric spatially multiplexed metalens (SMM) in the wavelength band from 1400 to 1700 nm. The proposed FSPS‐SMM is composed of three sets of off‐axis sub‐metalens simultaneously working for pairs of 0°/90°, 45°/135° linear polarization (LP), and left‐handed/right‐handed circular polarization (CP), respectively. Experimental results show that the optical resolution of each sub‐metalens of the fabricated FSPS‐SMM reaches the diffraction limit of the full‐aperture metalens although the area of each sub‐metalens is only 1/3 of the entire metalens, the averaged polarization extinction ratio of both LP and CP reaches 32.8:1, and the energy efficiency reaches 81.8% at the design wavelength and 60% averagely in the whole 300 nm bandwidth, which breaks the 50% limit of conventional polarizer‐based methods. The proposed design provides a new idea for high‐efficiency and high‐resolution full Stokes polarization‐spectral imaging and multichannel information processing.