XLO-II, a high-repetition rate X-ray laser oscillator

TL;DR

The paper proposes a second-generation high-repetition rate x-ray laser oscillator, XLO-II, capable of producing stable, coherent x-ray pulses at up to 125 kHz, enabling advanced scientific applications.

Contribution

It introduces the design and feasibility analysis of XLO-II, a high-repetition rate x-ray laser oscillator based on recent experimental results and simulations, extending current capabilities.

Findings

XLO-II can operate at up to 125 kHz repetition rate.

XLO-II will generate transform-limited, coherent x-ray pulses with tens of milliwatts.

The design leverages the LCLS-II-HE XFEL and CW superconducting linac technology.

Abstract

In a recent paper we proposed to build an x-ray laser oscillator (XLO) in the 6-10 keV range providing intense, stable, transform-limited, x-ray pulses based on population inversion driven by an x-ray pulse train generated by an x-ray free-electron laser (XFEL) operated at a repetition rate of about 100 Hz. Here we present an analysis of recent experimental results on x-ray lasing with population inversion, damage caused by the pump on the lasing medium, and optical cavities, together with theoretical/numerical simulations. Our findings suggest that it is possible to build and operate a second-generation x-ray laser oscillator, XLO-II, operating at up to 125 kHz repetition rate. XLO-II will be pumped by 6-10 keV x-ray SASE pulses, generated by the new LCLS-II-HE XFEL now under construction at SLAC National Accelerator Laboratory, utilizing a CW superconducting linac and capable of running at 1 MHz repetition rate. XLO-II will generate transform-limited, coherent x-ray pulses with an average power in the tens of mW range. It will open new experimental capabilities, for instance in fields like imaging, interferometry, and quantum x-ray optics. The main characteristics of XLO-II and its main components, including the optical cavity, will be discussed.