Quasimonoenergetic electron beams produced by colliding cross-polarized laser pulses in underdense plasmas

TL;DR

This paper demonstrates a new regime of electron injection in underdense plasmas using colliding cross-polarized laser pulses, showing that stochastic heating enables electron acceleration at higher laser intensities.

Contribution

It introduces and experimentally verifies a novel optical injection regime using cross-polarized laser pulses, expanding the understanding of electron acceleration mechanisms.

Findings

Electrons can be pre-accelerated by stochastic heating at laser collision.

Injection occurs at higher laser intensities with cross-polarized pulses.

A new injection regime is demonstrated both theoretically and experimentally.

Abstract

The interaction of two laser pulses in an underdense plasma has proven to be able to inject electrons in plasma waves, thus providing a stable and tunable source of electrons. Whereas previous works focused on the "beatwave" injection scheme in which two lasers with the same polarization collide in a plasma, this present letter studies the effect of polarization and more specifically the interaction of two colliding cross-polarized laser pulses. It is shown both theoretically and experimentally that electrons can also be pre-accelerated and injected by the stochastic heating occurring at the collision of two cross-polarized lasers and thus, a new regime of optical injection is demonstrated. It is found that injection with cross-polarized lasers occurs at higher laser intensities.