Broadband and High-Efficiency Multi-Tasking Silicon-Based Geometric-Phase Metasurfaces: A Review

Abstract

Silicon (Si)-based geometric phase metasurfaces are fantastic state-of-the-art light field manipulators. While the optical metasurfaces generally excel in the micro-control of light with supreme accuracy and flexibility, the geometric phase principle grants them the much-desired broadband phase manipulation property, free from material dispersion. Furthermore, adopting Si as their fundamental material serves as a critical step toward applicable practice. Thanks to the optical lossless feature and CMOS compatibility, Si-based metasurfaces are bestowed with high efficiency and fabrication conveniency. As a result, the Si-based metasurfaces can be perfectly integrated into Si-based optoelectronic chips with on-demand functions, trending to replace the conventional bulky and insufficient macroscopic optical devices. Here we review the origin, physical characteristics, and recent development of Si-based geometric-phase metasurfaces, especially underscoring their important achievements in broadband, high efficiency, and multitasking functionalities. Lastly, we envision their typical potential applications that can be realized in the near future.

High Efficiency Triple-Helix Solenoid Beam Generated by Dielectric Metasurface

“…Efficient incident beam phase modulation thus requires that the meta-atom should act like a halfwave plate. 31,32 A schematic illustration of the meta-atom is shown in Figure 1a. To determine the suitable dimensions (length L and width W) for these nanopillars, finite-element electromagnetic simulations are conducted using the commercial package COMSOL Multiphysics.…”

“…Metasurfaces, consisting of subwavelength structures engineered to manipulate light, have emerged as powerful tools in optics, demonstrating versatility in various applications such as second and third harmonic generation, − metalenses − and metaholograms. − Recently, metasurfaces have also been used to generate vortex beams, adding to their extensive range of capabilities. − Our metasurface is a Pancharatnam–Berry type (i.e., geometric phase) and based on a-Si nanopillar meta-atoms. Efficient incident beam phase modulation thus requires that the meta-atom should act like a halfwave plate. , A schematic illustration of the meta-atom is shown in Figure a. To determine the suitable dimensions (length L and width W ) for these nanopillars, finite-element electromagnetic simulations are conducted using the commercial package COMSOL Multiphysics.…”

Quasi-Freeform Metasurfaces for Wide-Angle Beam Deflecting and Splitting

“…Traditional optics for beam deflecting and splitting, such as lenses and triangular prisms, are bulky and heavy, which limits their applications in compact optical systems [ 5 , 6 ]. In recent years, metasurfaces emerged as a promising new device to replace or complement their traditional optical elements in the compact optical systems [ 7 , 8 ]. Metasurfaces are two-dimensional planar artificially constructed structure composed of subwavelength metallic or high-refractive-index dielectric antennae.…”