Bright, high-repetition-rate water window soft X-ray source enabled by nonlinear pulse self-compression in an antiresonant hollow-core fibre

TL;DR

This paper presents a compact, high-repetition-rate soft X-ray source using nonlinear pulse self-compression in an antiresonant hollow-core fibre, enabling table-top operation with applications in research and life sciences.

Contribution

It introduces a novel method combining pulse self-compression and phase-matched high-order harmonic generation in a single fibre for high-flux, high-repetition-rate SXR production.

Findings

First 100 kHz-class repetition rate SXR source.

Delivers 2.8×10^6 photons/sec/eV at 300 eV.

Compact, fibre-integrated setup for high-flux SXR generation.

Abstract

Bright, coherent soft X-ray (SXR) radiation is essential to a variety of applications in fundamental research and life sciences. So far, high photon flux in this spectral region can only be delivered by synchrotrons, free electron lasers or high-order harmonic generation (HHG) sources, which are driven by kHz-class repetition rate lasers with very high peak powers. Here, we establish a novel route toward powerful and easy-to-use SXR sources by presenting a compact experiment, in which nonlinear pulse self-compression to the few-cycle regime is combined with phase-matched HHG in a single, helium-filled antiresonant hollow-core fibre (ARHCF). This enables the first 100 kHz-class repetition rate, table-top SXR source, that delivers an application-relevant flux of 2.8*10^6 Photons/s/eV around 300 eV. The fibre-integration of temporal pulse self-compression (leading to the formation of the necessary strong-field waveforms) and pressure controlled phase-matching will allow compact, high repetition rate laser technology, including commercially available systems, to drive simple and cost-effective, coherent high-flux SXR sources.