Dynamically tunable infrared grating based on graphene-enabled phase switching of a split ring resonator [Invited]

Graphene plasmons with tunable resonance wavelengths and low loss have attracted considerable attention in the past decade. However, the weatk interaction between graphene and light, which is attributed to the low carrier concentration and small thickness of graphene, severely hinders the practical application of graphene plasmon. In the infrared wavelength range, graphene can act as a tunable load to modify both the resonance wavelength and the damping of metal plasmon, which has been successfully used for light intensity and phase modulations. In this work, a synthetic phase meta-atom composed of a split ring resonator and a graphene patch is designed with a switchable reflection phase of either 0 or π. The large phase tuning range arises from the graphene induced strong modification of metal plasmon. By arranging the 0/π phase bits in different spatial orders, one-dimensional grating with a dynamically tunable period and orientation can be obtained.