Ultrafast dynamics of surface electromagnetic waves in nanohole array on metallic film

TL;DR

This paper investigates the ultrafast behavior of surface electromagnetic waves on nanohole-patterned aluminum films using transient photomodulation, revealing a blueshift in transmission bands and modeling electron-phonon relaxation dynamics.

Contribution

It provides new insights into the ultrafast surface wave dynamics and challenges existing plasmon-polariton explanations with a Boltzmann equation-based model.

Findings

Observed a pronounced blueshift of the resonant transmission band.

Identified the role of plasma attenuation in the dynamics.

Modeled electron-phonon relaxation using Boltzmann equations.

Abstract

We study the ultrafast dynamics of surface electromagnetic waves photogenerated on aluminum film perforated with subwavelength holes array by means of transient photomodulation with 100 fs time resolution. We observed a pronounced blueshift of the resonant transmission band that reveals the important role of plasma attenuation in the dynamics and that is inconsistent with plasmon-polariton mechanism of extraordinary transmission. The transient photomodulation spectra were successfully modeled within the Boltzmann equation approach for the electron-phonon relaxation dynamics, involving non-equilibrium hot electrons and quasi-equilibrium phonons.