High-Q Metasurface Absorber Enabled by Symmetry Breaking in a Plasmonic Lattice

Area of Science:

• Plasmonics and Metamaterials
• Nanophotonics
• Light-Matter Interactions

Background:

• Metasurfaces enable spatiotemporal light control and enhanced light-matter interactions.
• High quality factor (Q) and near-field enhancement are key metrics for metasurface performance.
• Tunable optical signals (transmission/absorption) are crucial for photonic device applications.

Purpose of the Study:

• To engineer a plasmonic metasurface that achieves simultaneously high Q-factor and strong near-field enhancement.
• To demonstrate tunable optical absorption using engineered quasi-bound states in the continuum (qBIC) coupled to surface lattice resonances.
• To achieve wavelength tunability of optical signals in the near-infrared region.

Main Methods:

• Plasmonic metasurface fabrication and characterization.
• Engineering symmetry-breaking-induced quasi-bound states in the continuum (qBIC).
• Cooperative coupling of qBIC with surface lattice resonances.
• Theoretical analysis using temporal-coupled-mode theory (TCMT).
• Numerical simulations and experimental validation.

Main Results:

• Achieved high Q-factor (283 in experiments, 500 in simulation) and near-field enhancement (>10^4).
• Demonstrated tunable optical absorption through engineered qBIC and surface lattice resonances.
• Showcased tunable resonance wavelength across the near-infrared (700-1700 nm) via parametric scaling.

Conclusions:

• A novel strategy for plasmonic metasurfaces combining high Q, near-field enhancement, and tunable absorption is established.
• The engineered metasurface provides a versatile platform for advanced photonic devices.
• The demonstrated tunability across a broad spectral range opens avenues for infrared applications.