Self-Seeded FEL Wavelength Extension with High-Gain Harmonic Generation

TL;DR

This paper proposes a self-seeded HGHG FEL scheme to extend soft X-ray wavelengths, achieving coherent harmonic radiation at GW power levels with detailed performance analysis.

Contribution

It introduces a novel self-seeded HGHG scheme for wavelength extension in soft X-ray FELs, with comprehensive simulation-based performance evaluation.

Findings

Generation of coherent harmonic radiation at 1.52 nm

Achievement of GW-level power in harmonic radiation

Detailed analysis of FEL performance and fluctuations

Abstract

We study a self-seeded high-gain harmonic generation (HGHG) free-electron laser (FEL) scheme to extend the wavelength of a soft X-ray FEL. This scheme uses a regular self-seeding monochromator to generate a seed laser at the wavelength of 1.52 nm, followed by a HGHG configuration to produce coherent, narrow-bandwidth harmonic radiations at the GW level. The 2nd and 3rd harmonic radiation are investigated with start-to-end simulations. Detailed studies on the FEL performance and shot-to-shot fluctuations are presented.