Mid-infrared active metasurface based on Si/VO2 hybrid meta-atoms

Active metasurfaces whose optical properties can be tuned by an external stimulus have attracted great research interest recently. Introduction of VO 2 phase change material in all-dielectric metasurfaces has been demonstrated to modulate the resonance wavelength and amplitude in the visible to near-infrared wavelength range. In this study, we report a mid-infrared active metasurface based on Si / VO 2 hybrid meta-atoms. By incorporating VO 2 thin films in different locations of Si / VO 2 all-dielectric nanodisks, we demonstrate different modulation amplitude of the electric or magnetic resonance scattering cross sections, leading to drastically different transmission spectrum upon VO 2 insulator to metal phase transition. The physical mechanism is originated from the field profiles of the resonance modes, which interact with VO 2 differently depending on its locations. Based on this mechanism, we experimentally demonstrated a large modulation of the transmittance from 82% to 28% at the 4.6 μm wavelength. Our work demonstrates a promising potential of VO 2 -based active all-dielectric metasurface for mid-infrared photonic applications such as infrared camouflage, chemical/biomedical sensing, optical neuromorphic computing, and multispectral imaging.