Single-layered non-interleaved spin-insensitive metasurfaces for wavefront engineering

Abstract

Metasurfaces, two-dimensional (2D) or quasi-2D arrays of dielectric or metallic meta-atoms, offer a compact and novel platform to manipulate the amplitude, phase, and polarization of incoming wavefronts in a desired manner by engineering the geometry of meta-atoms. In polarization control, spin-insensitive metasurfaces have attracted significant attention due to the robustness of circular polarization against the beam misalignment and multi-path effects. Till now, several efforts have been made to realize polarization-insensitive metasurfaces for circularly polarized (CP) wavefront manipulation; however, these metasurfaces only consider the cross-polarization channels and keep the co-polarization channels abandoned. Such metasurfaces cannot be considered truly spin-insensitive, as one has to carefully choose the analyzer at output. Here, by combining the polarization-insensitive geometric phase and engineered propagation phase, we propose a spin-insensitive design principle based on metasurfaces that can perform identical functionality (on co-and crosspolarization channels) irrespective of the handedness of incident/transmitted light. As a proof of concept, we design and numerically realize two types of spin-insensitive wavefront engineering devices: (1) spin-insensitive meta-hologram and (2) spin-insensitive beam deflector with power splitting functionality. The proposed work is expected to open up new avenues for developing spin-independent metasurfaces-based devices.

Wideband Polarization‐Insensitive 1‐Bit Phase Manipulations with Co‐and Cross‐Polarized Conversions for LP and CP Waves

“…[39] Many scholars have dedicated their efforts to studying polarization and phase manipulation of CP waves. [21,[40][41][42][43][44][45][46] However, achieving wideband phase manipulation of the co-polarized or cross-polarized reflection wave for excitations of both LP and CP waves was rarely reported.…”