Generation of intense circularly polarized attosecond light bursts from relativistic laser plasmas

TL;DR

This paper demonstrates how to generate intense, circularly polarized attosecond light bursts from relativistic laser plasmas by controlling laser and plasma parameters, enabling new applications in ultrafast spectroscopy.

Contribution

It introduces a method to produce circularly polarized attosecond bursts using relativistic laser-plasma interactions with controlled laser and plasma parameters.

Findings

Polarization of attosecond bursts depends on laser pulse and plasma parameters.

Linearly polarized laser can produce elliptically polarized attosecond bursts.

Elliptically polarized laser can generate nearly circularly polarized attosecond bursts.

Abstract

We have investigated the polarization of attosecond light bursts generated by nanobunches of electrons from relativistic few-cycle laser pulse interaction with the surface of overdense plasmas. Particle-in-cell simulation shows that the polarization state of the generated attosecond burst depends on the incident-pulse polarization, duration, carrier envelope phase, as well as the plasma scale length. Through laser and plasma parameter control, without compromise of generation efficiency, a linearly polarized laser pulse with azimuth $\theta^i=10^\circ$ can generate an elliptically polarized attosecond burst with azimuth $|\theta^r_{\rm atto}|\approx61^\circ$ and ellipticity $\sigma^r_{\rm atto}\approx0.27$; while an elliptically polarized laser pulse with $\sigma^i\approx0.36$ can generate an almost circularly polarized attosecond burst with $\sigma^r_{\rm atto}\approx0.95$. The results propose a new way to a table-top circularly polarized XUV source as a probe with attosecond scale time resolution for many advanced applications.