High- <i>Q</i> Metasurface Absorber Enabled by Symmetry Breaking in a Plasmonic Lattice

Spatiotemporal control of light and enhancement of light-matter interactions by resonant metasurfaces are featured by the quality factor (<i>Q</i>) and the near-field enhancement. Simultaneously achieving high-<i>Q</i> and strong near-field enhancement is therefore a central goal of metasurfaces engineering. In addition, tunability of optical signals─transmittion or absorption─is highly desirable for photonic devices. Here, we open a way with a plasmonic metasurface to access high-<i>Q</i> (283 in experiments; 500 in simulation) and near-field enhancement (>10⁴) with tunable absorption by engineering symmetry-breaking-induced quasi-bound states in the continuum that are cooperatively coupled to surface lattice resonances in a plasmonic lattice. Moreover, the resonance wavelength is also tunable across the near-infrared (700-1700 nm) via simple parametric scaling. Here, we establish this strategy through temporal-coupled-mode-theory-based theoretical analysis, numerical simulation, and experimental validation.