Harmonic lasing of x-ray free electron laser: on the way to smaller and cheaper

TL;DR

This paper reviews recent advances in harmonic lasing of x-ray free electron lasers, highlighting its potential to create more compact and affordable FELs by utilizing higher harmonics, with experimental demonstrations across various spectral ranges.

Contribution

It provides a comprehensive review of the progress and future prospects of harmonic lasing in x-ray FELs, including recent proposals and experimental results.

Findings

Harmonic lasing has been experimentally demonstrated in low-gain FEL oscillators.

Harmonic lasing can enable smaller and cheaper x-ray FELs.

Future directions include harmonic lasing in single-pass FEL amplifiers.

Abstract

By utilizing higher harmonics of undulator radiation, harmonic lasing is helpful in the development of compact x-ray free electron lasers (FELs), i.e. reducing its costs and sizes. Harmonic lasing of FELs have been experimentally demonstrated in the low-gain FEL oscillators from terahertz, infrared to ultraviolet spectral range. Based on the current status and future directions of short-wavelength FELs in the worldwide, this paper reviews the progresses on harmonic lasing of x-ray FELs, mainly concentrating on the recently proposed harmonic lasing of x-ray FEL oscillators and further ideas on harmonic lasing of single pass x-ray FEL amplifiers.