AttoSHINE: Generation of continuous-wave terawatt-scale attosecond X-ray pulses at SHINE

TL;DR

This paper demonstrates that China's CW XFEL, SHINE, can generate terawatt-scale attosecond X-ray pulses at megahertz repetition rates using a self-chirping scheme, enabling advanced ultrafast science.

Contribution

It shows for the first time that a continuous-wave XFEL can produce intense attosecond X-ray pulses without additional hardware modifications.

Findings

SHINE can generate ~300 as X-ray pulses with terawatt peak power.

Attosecond pulses are achievable at megahertz repetition rates.

Self-chirping scheme enables pulse generation within existing setup.

Abstract

Attosecond X-ray pulses are a critical tool for tracking ultrafast electron dynamics in condensed matter, molecular systems, and strongly correlated materials. Recent breakthroughs have pushed X-ray free electron lasers (XFELs) into the attosecond domain, significantly surpassing their previous femtosecond capabilities. Building on these advancements, this work investigates the potential of the Shanghai High Repetition Rate XFEL and Extreme Light Facility (SHINE), China's first continuous-wave (CW) XFEL, to generate intense attosecond X-ray pulses, thereby offering transformative capabilities for X-ray science. Through comprehensive start-to-end simulations, we show that SHINE is capable of producing hard X-ray pulses with peak powers reaching the terawatt-scale and average pulse durations of approximately 300 as. This is achieved using a self-chirping scheme within the existing machine configuration, requiring no additional hardware. Our findings demonstrate that CW XFELs can generate intense attosecond X-ray pulses at megahertz repetition rates, opening new opportunities for real-time studies of electronic dynamics in complex systems.