Grating-Coupled Plasmonic Resonances in Symmetric 2D Gold Nanobump Grating: Theory Meets Experiments

Area of Science:

• Plasmonics and Nanophotonics
• Materials Science and Engineering
• Optical Spectroscopy

Background:

• Hybrid lattice plasmon resonances (HLPRs) arise from the interplay of surface plasmon polaritons (SPPs), localized surface plasmons (LSPs), and grating effects.
• These resonances exhibit narrow linewidths and tunability, making them promising for advanced optical applications.
• Understanding HLPR excitation is crucial for developing novel plasmonic devices.

Purpose of the Study:

• To investigate the diffraction-based excitation of HLPRs in a symmetric 2D gold nanobump grating.
• To experimentally explore the tunability of HLPR resonances with varying azimuthal and incidence angles, and polarization.
• To theoretically validate the origins of observed resonant peaks through spectral and near-field response calculations.

Main Methods:

• Experimental investigation of HLPR excitation in a 2D gold nanobump grating.
• Systematic variation of excitation parameters: azimuthal angle, incidence angle, and polarization.
• Theoretical modeling including spectral and near-field response calculations for resonance validation.

Main Results:

• Demonstrated diffraction-based excitation of HLPRs across multiple lattice planes.
• Quantified the tunability of HLPR resonances by controlling excitation geometry and polarization.
• Validated theoretical models that accurately predict spectral and near-field responses.

Conclusions:

• Symmetry and excitation geometry critically influence the characteristics of hybrid plasmonic modes.
• The study provides a framework for engineering highly tunable plasmonic platforms.
• Findings offer guidelines for optimizing HLPRs for biosensing and surface-enhanced spectroscopies.