Electrically Modulated Gap Interference for Tunable Plasmonic Metasurfaces

Plasmonic metasurfaces can precisely manipulate optical fields at the nanoscale, but the fixed properties after fabrication limit their applications. Here, we demonstrate electrically modulated plasmonic metasurfaces that enable continuous and reversible wavelength modulation with CMOS-compatible voltages below 5 V, tuning sensitivities of ∼0.5 nm/V, and modulation rates up to 10 Hz. These metasurfaces consist of dimethyl sulfoxide-immersed Ag nanoparticle lattices and Au electrodes on indium tin oxide (ITO)/quartz substrate, placed on a glass slide with an air gap or a single layer of polystyrene microspheres between them. The wavelength shift of surface lattice resonance is modulated by the interference mode when voltage is applied, as the air gap thickness increases due to thermal stress arising from the temperature difference between ITO and quartz. We anticipate that this work can provide novel insights into the tunable nanophotonic devices for optical imaging, display, and communications.