Plasmonic crystals for ultrafast nanophotonics: Optical switching of surface plasmon polaritons

TL;DR

This study demonstrates ultrafast control of surface plasmon polaritons in a perforated gold film using femtosecond laser pulses, revealing rapid electron dynamics and resonance shifts relevant for nanophotonic applications.

Contribution

It introduces a method to manipulate plasmonic dispersion with femtosecond pulses and provides detailed insights into electron dynamics in gold surfaces.

Findings

Plasmon resonance shifts occur within 200-800 fs after excitation.

Wood anomalies produce significant differential transmission and reflection.

Resonance magnitudes reach up to 3% at moderate pump fluences.

Abstract

We demonstrate that the dispersion of surface plasmon polaritons in a periodically perforated gold film can be efficiently manipulated by femtosecond laser pulses with the wavelengths far from the intrinsic resonances of gold. Using a time- and frequency- resolved pump-probe technique we observe shifting of the plasmon polariton resonances with response times from 200 to 800 fs depending on the probe photon energy, through which we obtain comprehensive insight into the electron dynamics in gold. We show that Wood anomalies in the optical spectra provide pronounced resonances in differential transmission and reflection with magnitudes up to 3% for moderate pump fluences of 0.5 mJ/cm^2.