Continuous relativistic high-harmonic generation from a kHz liquid-sheet plasma mirror

TL;DR

This paper demonstrates continuous high-harmonic generation at 1 kHz from a liquid-sheet plasma mirror driven by relativistic light, enabling stable extreme ultraviolet spectra and attosecond pulse trains, advancing high-power attosecond laser technology.

Contribution

It introduces a method for stable, high-repetition-rate high-harmonic generation using liquid-sheet plasma mirrors with precise control of plasma and waveform parameters.

Findings

Achieved 1 kHz high-harmonic generation with stable EUV spectra.

Produced quasi-continuous spectra corresponding to attosecond pulse trains.

Confirmed liquid sheet targets as promising for future high-power attosecond lasers.

Abstract

We report on continuous high-harmonic generation at 1 kHz repetition rate from a liquid-sheet plasma mirror driven by relativistic-intensity near-single-cycle light transients. Through precise control of both the surface plasma density gradient and the driving light waveform, we can produce highly stable and reproducible extreme ultraviolet spectral quasi-continua, corresponding to the generation of stable kHz-trains of isolated attosecond pulses in the time domain. This confirms the exciting potential of liquid sheet targets as one of the building blocks of future high-power attosecond lasers.