Electro-Optical Switching in a Nonlinear Metasurface

Abstract: Nonlinear metasurfaces are multifunctional photonic elements that generate and control light, enabling multiple proof-of-principle applications, such as in nonlinear holography, beam shaping, and nanoscale sources of entangled photon pairs. Active tuning of nonlinear metasurfaces will considerably expand their prospects for integrated photonics. Here, we demonstrate a highly-tunable metasurface device that combines electrical and optical switching in a broadband frequency conversion process. Our device employs electrically tunable hybrid graphene-gold plasmons to convert mid-infrared pulses into visible light by optical gating. A strong electrical modulation of the generated visible light is attained for a broad range of mid-infrared input frequencies, and this modulation is up to 3.5x stronger for the metasurface than for plain graphene. All-optical switching measurements indicate that the device can be optically switched at Terahertz rates. Our results may lead to new applications of metasurfaces such as ultrafast signal processing, nonlinear sensing, and optical transduction.