X-ray amplification from a Raman Free Electron Laser

TL;DR

This paper demonstrates a novel method for generating X-ray amplification using a Raman free electron laser driven by a high-intensity optical lattice, enabling ultra-compact coherent X-ray sources.

Contribution

It introduces a new approach for X-ray amplification via a Raman free electron laser utilizing a transverse optical lattice and provides theoretical and simulation validation.

Findings

X-ray amplification achieved with a mm-scale FEL.

Gain law derived and confirmed through simulations.

Potential for ultra-compact coherent X-ray sources.

Abstract

We demonstrate that a mm-scale free electron laser can operate in the X-ray range, in the interaction between a moderately relativistic electron bunch, and a transverse high intensity optical lattice. The corrugated light-induced ponderomotive potential acts simultaneously as a guide and as a low-frequency wiggler, triggering stimulated Raman scattering. The gain law in the small signal regime is derived in a fluid approach, and confirmed from Particle-In-Cell simulations. We describe the nature of bunching, and discuss the saturation properties. The resulting all-optical Raman X-ray laser opens perspectives for ultra-compact coherent light sources up to the hard X-ray range.