All-dielectric coding metasurface designs for spin-selective beam shaping and multichannel optical vortex beam manipulation

Abstract

Enhancing the information-carrying capacity of incident light using multifunctional metasurfaces have attracted considerable interests due to its promising applications in high-secure information encryption and communication. Incorporating spin-dependent wavefront control into all-dielectric designs is particularly important, as it not only allows information encoding based on the polarization state of light but also significantly enhances the channel capacity and security of optical communications. This paper explores all-dielectric coding metasurface that not only contribute to the fundamental understanding of spin-dependent light-matter interactions but also facilitates spin-switchable wavefront manipulation. To authenticate the proposed concept, we utilize a dielectric metasurface constructed by silicon (Si) nanobricks arranged in a square lattice. Through the strategic design of coding patterns, we manipulated the geometric phase and propagation phase at a wavelength of 780 nm to enable spin-dependent wavefront control, resulting in enhanced and complex functionalities, including manipulation of optical vortex beam (VB) carrying orbital angular momentum (OAM) with varied topological charges and a beam shaping that effectively split and divide the incident beam at an appropriate angle. In addition, the convolution operations further augment the functionality of all-dielectric coding metasurfaces, enabling more complex and multichannel manipulations. Our design method offers a simple and effective approach, which promises further applications in high-capacity encrypted communications, quantum information processing, non-invasive imaging and diagnostic systems.