Frequency-Domain and Space-Domain Reconfigurable Metasurfaces

Since its first appearance, digital reconfigurable metasurfaces have been developed rapidly in the past few years. This type of devices can dynamically modulate EM wave characteristic parameters (e.g., scattering amplitude, phase, and polarization), molding the wavefronts into shapes that can be arbitrarily designed, and greatly enhancing the nonlinear response of the system. With the deepening of research, reconfigurable metasurfaces have gradually transitioned from single-function devices to multi-functional modules and advanced information systems. In this chapter, the design methods and recent progress of exotic metasurfaces operating at frequency ranging from microwave to visible are reviewed first. Following the above basis, we emphatically discuss the concepts and the functions of the digital reconfigurable metasurfaces, including polarization conversion, beam-forming, and beam-shaping, orbital angular momentum (OAM) generation, etc.