Laser wakefield acceleration with mid-IR laser pulses

TL;DR

This paper demonstrates laser wakefield acceleration using mid-infrared pulses at 3.9 μm, achieving relativistic electron energies up to 12 MeV and showing increased charge compared to near-infrared pulses, supported by simulations and experiments.

Contribution

First demonstration of wakefield acceleration driven by ultrashort mid-infrared laser pulses with detailed scaling analysis and experimental validation.

Findings

Relativistic electrons up to ~12 MeV were accelerated.

Significant increase in accelerated charge compared to near-infrared pulses.

Scaling trends supported by particle-in-cell simulations and imaging.

Abstract

We report on the first results of laser plasma wakefield acceleration driven by ultrashort mid-infrared laser pulses (\lambda= 3.9 \mu m, 100 fs, 0.25 TW), which enable near- and above-critical density interactions with moderate-density gas jets. Relativistic electron acceleration up to ~12 MeV occurs when the jet width exceeds the threshold scale length for relativistic self-focusing. We present scaling trends in the accelerated beam profiles, charge and spectra, which are supported by particle-in-cell simulations and time-resolved images of the interaction. For similarly scaled conditions, we observe significant increases in accelerated charge compared to previous experiments with near-infrared (\lambda=800 nm) pulses.