Near-field imaging method based on graphene-metal split ring resonator

The invention provides a near-field imaging method based on a graphene-metal split ring resonator. The structure is characterized in that the structure is composed of a bottom-layer and top-layer periodically patterned metal layer 1, a middle dielectric layer 3 and a graphene layer 2 embedded in the dielectric layer 3. The metal layers of the bottom layer and the top layer adopt gold or silver and other conductors, and the medium layer in the middle is polyimide. Due to the fact that the structure shows symmetrical and asymmetrical modes parallel to and perpendicular to the symmetry axis under circular incident waves, the structure obtains the maximum circular dichroism at 1.181 THz by characterizing the reflectivity and the absorptivity under different circular polarization incident waves, and the value is 0.85. By applying bias voltage to change the Fermi level of the graphene, dynamic terahertz near-field imaging can be realized. The invention has the advantages of strong reflection, strong absorption, pol