Dispersive near-infrared metalens integrated with linear polarization filtering functionality

Abstract

The miniaturization and enhanced functionality of LiDAR systems present critical challenges in automotive sensing technologies, particularly in achieving efficient wide-angle beam scanning while maintaining compact form factors. We demonstrate a novel dual-wavelength polarization-selective concave metalens operating at 904 nm and 940 nm wavelengths, the standard operating wavelengths for LiDAR systems. By engineering rectangular TiO₂ nanopillars on a quartz substrate, we achieved simultaneous polarization filtering and concave phase profile functionality within a single metasurface layer. The optimized 600 nm × 600 nm unit cell design with 1.7 μm height nanopillars enables full 2π phase coverage while maintaining high transmission efficiency for the desired polarization state. Our fabricated metalens exhibits remarkable polarization extinction ratios (ER) of 124:1 and 102:1 at 904 nm and 940 nm wavelengths, respectively. Angular-resolved measurements demonstrate wide beam divergence angles of 148° and 138° at the respective wavelengths, with 50 % of total power contained within ± 38° and ± 25°.