Engineering Plasmonic Surface Lattice Resonances via a Nanoparticle Filling Factor.

Area of Science:

• Plasmonics
• Nanophotonics
• Materials Science

Background:

• Dielectric photonic crystals (PCs) exhibit scale-invariant band structures, allowing similar operation across different size regimes.
• Metallic nanoparticle arrays typically show dispersive behavior, unlike the scale-invariant nature of PCs.
• Surface lattice resonance (SLR) modes in metallic nanoparticle arrays, under coherent coupling, show similarities to dielectric PC behavior.

Purpose of the Study:

• To investigate the influence of the filling factor on the surface lattice resonance (SLR) wavelength in 2D metallic nanoparticle arrays.
• To explore the potential for scale-invariant behavior in plasmonic systems analogous to dielectric PCs.
• To establish a geometrical rule for controlling plasmonic resonances in nanoparticle arrays.

Main Methods:

• Experimental studies of 2D nanoparticle periodic arrays.
• Finite-difference time-domain (FDTD) simulations.
• Analysis of the relationship between filling factor and SLR wavelength.

Main Results:

• Demonstrated that two distinct 2D nanoparticle arrays with identical filling factors and lattice periods support SLRs at the same wavelength.
• Identified the filling factor as a key parameter determining SLR wavelength in the coherent coupling regime.
• Showcased scale-invariant behavior in plasmonic nanoparticle arrays.

Conclusions:

• The filling factor provides a simple geometrical rule to control plasmonic resonances in nanoparticle arrays.
• SLRs in metallic nanoparticle arrays can mimic the scale-invariant properties of dielectric PCs.
• This insight enables the rational design of substrates for sensing, photocatalysis, and surface-enhanced spectroscopies.