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

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.