Time-resolved analysis of strong-field induced plasmon oscillations in metal clusters by spectral interferometry with few-cycle laser fields

TL;DR

This paper introduces a spectral interferometry method for real-time imaging of plasmon oscillations in metal clusters, achieving sub-femtosecond resolution to study ultrafast electron dynamics under strong laser fields.

Contribution

It presents a novel nonlinear spectral interferometry technique for ultrafast imaging of plasmon oscillations in gas phase metal clusters, enabling detailed analysis of their dynamics.

Findings

Plasmon period and lifetime can be extracted with sub-fs resolution.

The method reveals increase of plasmon lifetime with laser intensity.

Access to nonlinear response effects like ionization-induced contraction.

Abstract

We propose a scheme for ultrafast real-time imaging of laser-induced collective electron oscillations (Mie plasmons) in gas phase metal clusters by interferometrically stable scanning of two intense few-cycle optical laser pulses. The feasibility of our nonlinear spectral interferometry method with experimentally accessible observables is tested in a theoretical case study on simple-metal clusters (Na$_{147}$). The results show that the plasmon period and lifetime as well as the phase and relative amplitude of the collective electron motion can be extracted with sub-fs resolution. The access to nonlinear response effects, as the demonstrated increase of the plasmon lifetime with laser intensity due to ionization-induced contraction of the electron cloud, opens up vast opportunities for interrogating ultrafast many-particle dynamics in nanosystems under strong laser fields with unprecedented resolution.