Orbital angular momentum multiplexing holography based on multiple polarization channel metasurface

Abstract

As a high-degree-of-freedom approach to manipulate the electromagnetic wave, metasurfaces are widely used in high-capacity information technology. Extensive investigations have explored multiplexing techniques using polarization, incident angle, wavelength, and infinite-dimensional multiplexing through Orbital Angular Momentum (OAM). However, due to the limited spatial resolution and array size of the metasurface, the number of multiplexing channels that can be actually realized is limited. Therefore, research on the combination of OAM multiplexing and polarization degrees of freedom is of great significance. Here, we propose and experimentally demonstrate a metasurface holography multiplexing scheme based on multiple polarization channels combined with OAM. Taking advantage of the orthogonal independence of spin angular momentum and orbital angular momentum, multiple OAM multiplexing holograms are constructed in multiple different spin-polarization channels. Utilizing the well-established compatibility between OAM multiplexing and polarization multiplexing, we successfully integrated two multiplane holograms and 15 OAM multiplexing holograms on a single metasurface. Subsequently, we introduced an optical nested encryption framework designed for parallel communication. This work facilitates high-capacity and high-security holography by employing multiplexing metasurfaces, thereby providing innovative design concepts for optical communication, information encryption, and related domains.