Convolution Operation on Pancharatnam-Berry Coding Metasurfaces in Visible Band

Coding metasurfaces bring photonic design into a new era for their convenience in manipulating elec-tromagnetic waves in a programmable way. Different coding patterns can be further convoluted to give rise to nontrivial effects such as multiple beam steering, simultaneous control of surface and space waves, and the integration of multiple functionalities. However, previous experimental works have been limited to low frequencies. Extending convoluted coding metasurfaces to optical frequency can significantly reduce the size of structures, and therefore facilitate their applications in optical circuits. Here, we experimentally demonstrate a Pancharatnam-Berry metasurface designed by convoluting two distinct coding patterns. Such a metasurface exhibits integrated functionalities: the optical spin Hall effect and spin to orbital angu-lar momentum conversion, which are robust over a broad visible band and a wide range of incident angles. Our work represents an important step towards multifunctional coding metasurfaces at optical frequency based on convolution operation.