Nanocorrugation-Induced Selectivity and Tunability of Plasmon Resonances: Application to Resonance Energy Transfer

Achieving precise selectivity and tunability of plasmonic peaks is essential to regulate optoelectronic phenomena and the resonance energy transfer (RET) rate. Combining finite-difference time-domain (FDTD) simulations with a newly developed phenomenological plasmon oscillation model, we elucidate how surface nanostructuring affects the wavelength of localized surface plasmon polaritons (LSPPs) and the coupling between nearby donor and acceptor molecules. Surface nanocorrugation induces transverse electron oscillations along with longitudinal electron oscillations, with high- and low-intensity electric fields located near the neck and the bulb regions of the corrugated nanorods, respectively. Increasing the nanocorrugation height leads to nonlinear redshifts of LSPPs, while variations in periodicity cause anomalous shifts. The maximum redshift is observed at the periodicity where the spatial pattern of the plasmonic peak is fully in phase with the surface morphology. Additionally, the selectivity in the redshift of even- or odd-order LSPP multipoles depends on matching between the local electric field energy and the surface capacitance. Theoretical predictions show strong agreement with experimental data reported in literature. This study presents a method based on local curvature for achieving precise control in the selectivity and broad tunability of LSPPs wavelength for enhanced RET.