Detailed formation mechanism of sharp plasmonic lattice modes on Au hemi-ellipsoid arrays in inhomogeneous environment

Abstract

Abstract Plasmonic lattice modes (PLM) on the periodic arrays of Au hemi-ellipsoids on quartz substrates (inhomogeneous environment) is demonstrated experimentally. It is found that formation of PLM results from the coupling between the resonance of Au hemi-ellipsoids and the diffracted waves inside the substrates. The quality factor of PLM can be attributed to three factors: the weakening of zero-order diffracted waves, the strengthening of hemi-ellipsoid’s resonance and the match between the period of the arrays and nanoparticles’ resonance wavelength. The simulated results show that the structural parameters, such as the radius of Au hemi-ellipsoid and the environmental refractive index, have effects on the quality factor of PLM. In addition, experimental results also indicate that the backward incidence results in a sharper transmission valley than the forward incidence.