Effects of Laser Polarization and Color on Hybrid Laser Wakefield and Direct Acceleration

TL;DR

This paper investigates how using two laser pulses with different polarizations or frequencies can enhance hybrid laser wakefield and direct acceleration, leading to higher electron energies and reduced sensitivity to timing.

Contribution

It introduces a method to improve LWDA by employing dual laser pulses with different polarizations or frequencies, optimizing acceleration performance.

Findings

Orthogonal polarization of same-frequency pulses improves acceleration.

Frequency-doubled DLA pulse enhances electron energy compared to single-frequency.

Hybrid LWDA becomes less sensitive to pulse timing variations.

Abstract

We demonstrate that hybrid laser wakefield and direct acceleration (LWDA) can be significantly improved by using two laser pulses with different polarizations or frequencies. The improvement entails higher energy and charge of the accelerated electrons, as well as weaker sensitivity to the time delay between the leading (pump) pulse responsible for generating the wakefield, and the trailing laser pulse responsible for direct laser acceleration (DLA). When the two laser pulses have the same frequency, it is shown that it is advantageous to have their polarization states orthogonal to each other. A specific scenario of a frequency-doubled ($\lambda_{\rm DLA}=\lambda_{\rm pump}/2$) DLA laser pulse is also considered, and found to be an improvement over the single-frequency ($\lambda_{\rm DLA} = \lambda_{\rm pump}$) scenario.