Hierarchical Hybridization in Plasmonic Honeycomb Lattices

Abstract

This paper reports hierarchical hybridization as a mode-mixing scheme to account for the unique optical properties of non-Bravais lattices of plasmonic nanoparticles (NPs). The formation of surface lattice resonances (SLRs) mediated by localized surface plasmons (LSPs) of different multipolar orders (dipole and quadrupole) can result in asymmetric electric near-field distributions surrounding the NPs. This asymmetry is because of LSP hybridization at the individual NP level from LSPs of different multipole order and at the unit cell level (NP dimer) from LSPs of the same multipole order. Fabricated honeycomb lattices of silver NPs exhibit ultrasharp SLRs at the Γ point that can also facilitate nanolasing. Modeling of the stimulated emission process revealed that the multipolar component of the lattice plasmon mode was responsible for feedback for lasing. By leveraging multipolar LSP responses in Al NP lattices, we achieved two distinct Γ point band-edge modes from a single honeycomb lattice. This work highlights how multipolar LSP coupling in plasmonic lattices with a non-Bravais symmetry has important implications for the design of SLRs and their associated plasmonic near-field distributions. These relatively unexplored degrees of freedom can decrease both ohmic and radiative losses in nanoscale systems and enable SLRs to build unanticipated connections among photonics and nanochemistry.

Nanostructured Surfaces as Plasmonic Biosensors: A Review

“…Adapted with permission. [118] Copyright 2019, American Chemical Society. d-1) SEM images of single and double Au nanodot lattices, d-2) spectral response of the single particle array for mediumand substrate-related modes in direct geometry, d-3) spectral response of the double particle array for medium-and substrate-related modes in ATR geometry, d-4) phase response when superstrate pass from a solution 80%/20% ethanol/water to pure ethanol (the inset shows the corresponding phase shifts).…”

“…Indeed, lattices of honeycomb-arranged nanoparticles generally exhibit better performance as compared to rectangular and hexagonal ones. [20] In this regard, Li et al [118] fabricated a honeycomb array of Al nanodisks by soft lithography (Figure 7c-1) able to support two high-quality SLRs over the visible and NIR range simultaneously (Figure 7c-2). This is a peculiar feature exhibited by the honeycomb lattice and, ultimately, it takes place thanks to its non-Bravais nature as suggested by the lack of the effect in similar hexagonal lattices.…”

“…c-1) SEM image of the honeycomb lattice of Al nanodisks, c-2) measured transmission spectrum, c-3) simulated electric field distributions of the unit cell at Γ 1 wavelength in the x-y plane (top panel) and at Γ 2 wavelength in the x-z plane (bottom panel). Adapted with permission [118]. Copyright 2019, American Chemical Society.…”

Diffractive dipolar coupling in non-Bravais plasmonic lattices

“…Calculations of the p-polarized SLR are in very good agreement with what is reported in ref. 47 (see Fig. S8 in the ESI †).…”

“…Inspired by the recent development in material science and the ground-breaking discovery of a new class of two-dimensional non-Bravais materials, non-Bravais plasmonic lattices started receiving attention. 31,[44][45][46][47][48] Even though the equations governing atomic and optical lattices are different, analogies can be drawn based on translation invariance and Bloch theorem. The attractive physical properties of graphene and transition metal dichalcogenides trace back to their crystalline honeycomb structure and the presence of nonequivalent K points in the reciprocal space.…”