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

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 $\hat{I}{¸}^i=10^{\circ }$ can generate an elliptically polarized attosecond burst with azimuth $|\hat{I}{¸}_{\mathrm{atto}}^r|\approx 61^{\circ }$ and ellipticity $\ddot{I}{ƒ}_{\mathrm{atto}}^r\approx 0.27$; while an elliptically polarized laser pulse with $\ddot{I}{ƒ}^i\approx 0.36$ can generate an almost circularly polarized attosecond burst with $\ddot{I}{ƒ}_{\mathrm{atto}}^r\approx 0.95$. 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.