Spectral and temporal modulations of femtosecond SPP wave packets induced by resonant transmission/reflection interactions with metal-insulator-metal nanocavities

TL;DR

This paper investigates how femtosecond surface plasmon polariton wave packets interact with metal-insulator-metal nanocavities, revealing spectral modulations and potential for pulse shaping through resonance tuning.

Contribution

It demonstrates the spectral and temporal modulation effects of MIM nanocavities on SPP wave packets and introduces their use as tunable spectral filters.

Findings

MIM structures cause strong spectral modulations in SPP wave packets.

Resonance tuning enables control over pulse duration and timing.

MIM acts as a Fabry-Perot etalon-type filter.

Abstract

To study the dynamical optical interactions of nano-scaled metal-insulator-metal (MIM) structures in temporal-frequency domain, femtosecond surface plasmon polariton (SPP) wave packets propagate over a surface with a MIM structure. The resonance nature of the SPP-cavity interaction is reflected as strong modulations in the spectra of transmitted and reflected SPP wavepackets, which show peaks and valleys, respectively, corresponding to the MIM cavity's eigenmode. These features indicate that the MIM structure acts as a Fabry-Perot etalon-type spectrum filter. With appropriate tuning of the resonance frequency of the cavity, one can extract a wave packet with a narrower time duration and temporally shifted intensity peak.