Full-space wavefront control enabled by a bilayer metasurface sandwiching 1D photonic crystal

Metasurfaces, composed of sub-wavelength structures, have a powerful capability to manipulate light propagations. However, metasurfaces usually work either in pure reflec-tion mode or pure transmission mode. Achieving full-space manipulation of light at will in the optical region is still challenging. Here we propose a design method of full-space meta-device containing a bilayer metasurface sandwich-ing 1D photonic crystal to manipulate the transmitted and reflected wave independently. To provide a proof-of-concept demonstration, a device is proposed to show the light focusing in transmission and a vortex beam in reflec-tion. Meanwhile, a device focusing the reflected light with oblique 45 degrees incidence and the transmitted light with normal incidence is designed to indicate its application potential in augmented reality (AR) application. Our design provides a promising way to enrich the multifunctional meta-devices for potential applications. (c) 2023 Optica Publishing Group