High-Speed Transmission Control in Gate-Tunable Metasurfaces Using Hybrid Plasmonic Waveguide Mode

Dynamic control of light based on gate-tunable metasurfaces has revolutionized traditional optoelectronic devices due to its unprecedented compactness and versatile functionalities. However, these devices are typically based on metal-insulator-metal geometries that enable field-effect modulation of only reflected light. Transmittance modulation techniques based on dielectric metasurfaces, despite their large modulation depth, have a disadvantage of low modulation speed due to high resistance of dielectric materials. Here, a high-efficiency transmittance modulator that enables high switching speed, as well as large modulation depth, is demonstrated using indium-tin-oxide-based metasurfaces. To realize these devices, the hybrid plasmonic waveguide mode is used which allows electromagnetic energy storage within the nanoscale permittivity-tunable region between metal and high-refractive dielectric layers. Experimental measurements reveal a change in the transmittance (≈33%) by applying 6 V gate bias, and a fast modulation speed (≈826 kHz of 3 dB cut-off frequency). This work provides a promising avenue for developing ultracompact optical components such as dynamic holograms, lenses with active focal lengths, or spatial light modulators.