Bright high-order harmonic generation with controllable polarization from a relativistic plasma mirror

TL;DR

This paper introduces a novel laser-plasma method to generate bright, controllably polarized XUV pulses, enabling advanced material studies with a practical and efficient approach using relativistic plasma mirrors.

Contribution

It proposes and numerically demonstrates a new scheme for producing bright, polarized XUV pulses via laser-plasma interactions, expanding capabilities beyond existing free-electron laser sources.

Findings

Generation of circular and elliptical XUV pulses with controlled polarization.

The polarization state is tunable by adjusting laser-plasma parameters.

The mechanism is explained by the relativistically oscillating mirror model.

Abstract

Ultrafast extreme ultraviolet (XUV) sources with a controllable polarization state are powerful tools for investigating the structural and electronic as well as the magnetic properties of materials. However, such light sources are still limited to only a few free-electron laser facilities and, very recently, to high-order harmonic generation from noble gases. Here we propose and numerically demonstrate a laser-plasma scheme to generate bright XUV pulses with fully controlled polarization. In this scheme, an elliptically-polarized laser pulse is obliquely incident on a plasma surface, and the reflected radiation contains pulse trains and isolated circularly- or highly-elliptically-polarized attosecond XUV pulses. The harmonic polarization state is fully controlled by the laser-plasma parameters. The mechanism can be explained within the relativistically oscillating mirror model. This scheme opens a practical and promising route to generate bright attosecond XUV pulses with desirable ellipticities in a straightforward and efficient way for a number of applications.