Modified Coupled-Mode Theory on Fluorescent Surface Lattice Resonance

Abstract

Surface lattice resonance (SLR) is a plasmonic-photonic mode that is supported on nanoparticle arrays, originating from the coupling between in-plane diffraction modes and the localized surface plasmon resonance or Mie resonance on nanoparticles [1]. Previous works have shown that SLR is capable in significantly enhancing the light-matter interaction of fluorescent dye molecules and can enhance both the in-coupling efficiency as well as the directional out-coupling enhancement of the fluorescent emission [2]. SLR enhances the fluorescence absorption efficiency by confining the electromagnetic field into the vicinity of the nanoparticle array and inducing a strong light-matter interaction between the incident field and the fluorescent molecules [3]. SLR also enhances the spontaneous emission rate of fluorescent molecules through increased local density of state near the nanoparticle array, commonly known as the Purcell effect [4]. The nanoparticle array also controls the emission direction through diffraction.