Multiple surface lattice resonances in gold nano-hexagonal prism arrays

Abstract

Multiple surface lattice resonance exhibits great promise in applications connected to multi-wavelength because it can simultaneously decrease the radiation loss of the overall system near numerous resonance points, improving the interaction between light and matter. Since the hexapole localized surface plasmon resonance (LSPR) mode has equivalent dipole moments in the directions of both X and Y, it has the ability to disperse electromagnetic waves in the plane's X and Y directions, making it possible for the hexapole LSPR to couple with Rayleigh anomalies in two orthogonal directions. This paper proposes a gold nano-hexagonal prism array structure that can excite multiple surface lattice resonances without designing complex polymer structures. Due to the particularity of the regular hexagonal prism structure, the tip effect is introduced to enhance the hexagonal LSPR mode in a targeted manner. The numerical simulation and modal field analysis results show that the hexagonal LSPR of the gold nano-hexagonal prism array structure can couple with two periodic Rayleigh anomalies in the plane, resulting in two surface lattice resonance peaks. The structure can also be excited by incident light to generate an out-of-plane dipole mode, which couples with Rayleigh anomalies to form a surface lattice resonance peak. This work provides new understanding and data support for the design of multiple surface lattice resonance devices by presenting in detail the properties of the structure's three surface lattice resonance peaks varying with structural parameters.