Active Terahertz Modulator and Slow Light Metamaterial Devices with Hybrid Graphene-superconductor Coupled Split-ring Resonator Arrays

The dynamically tunable terahertz (THz) waves and electromagnetically induced transparency (EIT) in coupled hybrid superconducting niobium-graphene split-ring resonator arrays are investigated. Active modulation of THz waves is studied through two different approaches. Thermal tuning of THz amplitude and group delay is observed due to the temperature sensitivity of the niobium superconductor. Stronger photoresponses are observed when niobium is superconducting. The electrical tuning of the integrated hybrid device is accomplished through the integration of graphene patches with the superconducting circuit. The modulation of resonance strength and group delay is observed due to damping of the dark mode resonance in coupled split-ring resonator arrays. The proposed chip-scale device provides a route toward the implementation of active cryogenic THz devices.