Robust and reconfigurable surface lattice resonance in Ag tetramer array/VO₂ hybrid plasmonic metasurfaces

While static dielectric resonant metaphotonics is reaching maturity, challenges remain in the design and fabrication of efficient reconfigurable metasurface structures. A promising approach to tunable metasurfaces is to incorporate phase change materials (PCMs) into photonic structure design. Here, we report a reconfigurable surface lattice resonance (SLR) in an Ag tetramer array/thin VO₂ layer/Al mirror hybrid metasurface in near-infrared frequencies. We show that the unique SLR can be excited by diffractive coherent coupling of localized surface plasmon resonance (LSPR) in Ag tetramer arrays, exhibiting a narrow Fano resonance in the reflective spectra response. The scattered power of multipoles and near-field distributions shows that the electric dipoles dominate the SLR. The reflection spectral response of SLR can be dynamically tuned by leveraging the thermally driven phase change of VO₂. The modulation depth can reach up to 82.5% with a 14 nm line width at normal incidence. More intriguingly, we find that the resonant wavelength, linewidth, and large modulation depth of the SLR are highly robust against variations in structural parameters and remain essentially independent of polarization orientation. With high modulation depth and a robust resonant frequency, the SLR offered by this hybrid metasurface may enable a range of applications, including efficient optical switches and memories, thermal photovoltaics, tunable photodetectors, and reconfigurable displays.