Independent control of circularly polarized light with exceptional topological phase coding metasurfaces
Yicheng Li, Shicheng Wan, Shaoxuan Deng, Zhengwei Deng, Bo Lv, Chunying Guan, Jun Yang, Andrey Bogdanov, Pavel A. Belov, Jinhui Shi
Abstract
Exceptional points, as degenerate points of non-Hermitian parity-time symmetric systems, have many unique physical properties. Due to its flexible control of electromagnetic waves, a metasurface is frequently used in the field of nanophotonics. In this work, we developed a parity-time symmetric metasurface and implemented the 2 π topological phase surrounding an exceptional point. Compared with Pancharatnam-Berry phase, the topological phase around an exceptional point can achieve independent regulation of several circular polarization beams. We combined the Pancharatnam-Berry phase with the exceptional topological phase and proposed a composite coding metasurface to achieve reflection decoupling of different circular polarizations. This work provides a design idea for polarimetric coding metasurfaces in the future.