Fig. 1. Schematic illustration of the device based on graphene. From top to bottom, there are the gold grating layer, Al₂O₃ dielectric medium, graphene sheet, and SiO₂/Si layer. Here, d and w are respectively the period and the width of the gold strips. The structure sketched by the dotted line can be served as cavity and Lis the cavity length.

Fig. 2. (a) Frequency dependence of the light transmission of the structure with (black solid line) and without graphene (red solid line); (b) frequency dependence of the light absorption of the structure with (black solid line) and without graphene (red solid line).

Fig. 3. Spatial distribution of the electric field (a) and (b) components of light field along the x direction in graphene sheet for different factor .

Fig. 4. The electron density dependence of the plasmon polariton modes (black solid lines) induced by coupling between cavity photons ( , red dotted lines) and plasmon modes in graphene (red solid line).