High-efficiency and tunable circular dichroism in chiral graphene metasurface

Circular dichroism (CD) response is extremely important for dynamic polarization control, chiral molecular sensing and imaging, etc. Here, we numerically demonstrated high-efficiency and tunable CD using a symmetry broken graphene-dielectric-metal composite microstructure. By introducing slot patterns in graphene ribbons, the metasurface exhibits giant polarization-selective absorption for circularly polarized (CP) wave excitations. The maximum CD reaches 0.87 at 2.78 THz, which originates from the localized surface plasmon resonances in patterned graphene. Besides, the operating frequency and magnitude of CD are dynamically manipulated by gating graphene's Fermi energies. The proposed chiral graphene metasurface with high-efficiency and tunable capability paves a way to the design of active CD metasurfaces.

Automated summary

In this paper, we demonstrated high-efficiency and tunable circular dichroism (CD) using a symmetry broken graphene-dielectric-metal composite microstructure. The introduction of slot patterns in graphene ribbons leads to giant polarization-selective absorption for circularly polarized wave excitations, and the operating frequency and magnitude of CD can be dynamically controlled by gating graphene's Fermi energies.