Abstract:

Linear-to-circular polarizer (LCP) is a device that can convert linear polarization into circular polarization, and is widely used in the wireless communication, spectroscopy, quantum materials, and some other areas. The conventional LCPs are based on a quarter-wave plate made by some birefringent crystals, which is usually bulky and can only work at a single polarization angle and frequency. The advent of metasurfaces provides a new avenue towards practical LCPs. Several metasurface-based LCPs are proposed and successfully demonstrated in the microwave, terahertz, and optical regions based on different design principles. Compared with conventional LCPs, metasurface-based polarizers have the advantages of subwavelength thickness, high efficiency, and broad bandwidth. However, most of them still work at a single polarization angle. Moreover, in the optical region, the size of polarizers is greatly limited by the fabrication methods. In this presentation, a linear-to-circular polarizer valid for a broad polarization angular span is proposed, and it can be fabricated by using interference lithography to achieve a cm-scale size.