Spin-controlled multifunctional metasurfaces

Abstract

Multitasking shared-aperture systems have initially emerged as radar phased array antennas. Recently, the shared-aperture concept has been suggested as a platform for multifunctional optical phased array antennas, accomplished by a reflective metasurface [1]. Metasurfaces consist of metallic or dielectric subwavelength nanoantennas, capable of manipulating light by controlling the local amplitude and phase of an incident electromagnetic wave [2-6]. An effective control of the electromagnetic response can be achieved by a geometric phase mechanism implemented within a metasurface, enabling spin-controlled phase modulation. Shared-aperture geometric phase metasurface (GPM) paves the way for multifunctional nano-optical device. Shared-aperture interleaved phased arrays are formed by the random interspersing of sub-arrays, thus resulting in a device with high flexibility in multifunctional wavefront generation and the angular resolution of the shared aperture. Each sub-array is associated with a specific phase function, sparsely sampled at randomly chosen lattice points. We presented multifunctional spin-dependent dielectric metasurfaces, and demonstrated multiple-beam technology for complete real-time control and measurement of the fundamental intrinsic properties of light, including frequency, polarization, and orbital angular momentum (OAM) [7].