Plasmonic characteristics of the structure with double graphene layers immersed in chiral media and applications in detection of chirality

The propagating behavior of surface plasmons in chiral media is different from that in achiral media. By comparing the propagation behavior of SPPs, the chirality of the environment can be evaluated. We theoretically reveal the features of SPPs in a structure with two individual graphene sheets surrounded by chiral environment. A more universal dispersion relation covering the achiral cases is obtained. The effects of the chirality of medium and the chemical potential of graphene on the SPPs are explored. Besides, a novel method of detecting the chirality of the environment based on the lateral optical force and torque is proposed. The characteristics of the structure may enrich the surface plasmonic wave theory on the waveguides with multiple graphene sheets and provide new opportunities for the design of more compact nanophotonic functional devices and novel biosensors.