Optimizing the ionization and energy absorption of laser-irradiated clusters

TL;DR

This paper uses 3D particle-in-cell simulations to identify optimal laser wavelengths for maximum energy absorption in xenon clusters, revealing a resonance condition that enhances ionization efficiency during ultrashort pulses.

Contribution

It introduces a method to predict the optimal laser wavelength for energy absorption in clusters based on transient Mie-resonance, improving understanding of laser-cluster interactions.

Findings

Optimal wavelength aligns with the transient linear Mie-resonance.

Single ultrashort pulses at this wavelength achieve higher absorption than dual-pulse setups.

Resonance enhances ionization and energy absorption efficiency.

Abstract

It is known that rare-gas or metal clusters absorb incident laser energy very efficiently. However, due to the intricate dependencies on all the laser and cluster parameters it is difficult to predict under which circumstances ionization and energy absorption is optimal. With the help of three-dimensional particle-in-cell simulations of xenon clusters (up to 17256 atoms) we find that for a given laser pulse energy and cluster an optimum wavelength exists which corresponds to the approximate wavelength of the transient, linear Mie-resonance of the ionizing cluster at an early stage of negligible expansion. In a single ultrashort laser pulse, the linear resonance at this optimum wavelength yields much higher absorption efficiency than in the conventional, dual-pulse pump-probe set-up of linear resonance during cluster expansion.