Mid-infrared 2D TaSe₂ plasmonic metasurfaces with periodic hole arrays

Mid-infrared plasmonic metasurfaces have attracted significant interest for a wide range of applications. While conventional metals are commonly used in plasmonic metasurfaces, metallic transition-metal dichalcogenides with high carrier densities and infrared plasmonic response have emerged as attractive alternatives. Here, we demonstrate the mid-infrared TaSe₂ plasmonic metasurfaces with periodic hole arrays. It is observed that two plasmonic resonance modes in mid-infrared frequency range are supported in the TaSe₂ metasurface. The simulated electromagnetic field distributions reveal that the two plasmonic resonances represent a fundamental (1, 0) mode and a higher-order (1, 1) mode. By increasing the array period, a continuous redshift of the resonance frequency is observed for each mode, consistent with the inverse scaling predicted by the grating coupling condition. The demonstrated results will advance the development of 2D-material-based mid-infrared photonic devices as a promising platform for applications in thermal emission control, molecular sensing, and infrared detection.