Surface lattice resonances for high-performance sensing: a study on gold nanoparticle arrays

Area of Science:

• Nanophotonics
• Plasmonics
• Sensing Technology

Background:

• Localized surface plasmon resonances (LSPRs) are crucial for nanoparticle optical properties.
• Diffractive coupling in nanoparticle arrays can lead to emergent phenomena like surface lattice resonances (SLRs).
• Enhancing the sensitivity and quality factor of plasmonic sensors is a key challenge in nanophotonics.

Purpose of the Study:

• To systematically explore surface lattice resonances in periodic arrays of gold nanoparticles.
• To analyze the impact of nanoparticle geometry and lattice configuration on sensing performance.
• To experimentally validate the enhanced sensing capabilities of these arrays.

Main Methods:

• Finite element method (FEM) simulations using COMSOL Multiphysics.
• Analysis of nanoparticle geometry (spheres, disks, rods) and lattice configuration.
• Experimental confirmation of hybrid spectral features and sensing performance.

Main Results:

• Periodic arrays showed significantly enhanced sensing capabilities compared to isolated nanoparticles.
• Quality factors were improved by an order of magnitude, and bulk sensitivity exceeded 100 nm/RIU.
• Experimental validation confirmed narrower resonances and improved sensing performance due to collective effects.

Conclusions:

• Periodic gold nanoparticle arrays, empowered by surface lattice resonances, offer strong potential for high-performance sensing.
• Diffractive coupling and periodicity are key to achieving enhanced quality factors and sensitivity.
• Even simple geometries in periodic arrays can yield high-performance sensors.