Laser-like X-ray Sources Based on Optical Reflection from Relativistic Electron Mirror

TL;DR

This paper introduces a new method to produce uniform relativistic electron layers using a reflected laser pulse from an additional foil, enabling coherent X-ray generation through Thomson backscattering.

Contribution

It presents a novel scheme combining an extra reflective foil and a laser pulse to generate uniform relativistic electron layers for enhanced X-ray sources.

Findings

Analytic theory confirms the formation of uniform electron layers.

2D-PIC simulations demonstrate high relativistic gamma-factors.

The scheme achieves Doppler-shifted backscattering with high efficiency.

Abstract

A novel scheme is proposed to generate uniform relativistic electron layers for coherent Thomson backscattering. A few-cycle laser pulse is used to produce the electron layer from an ultra-thin solid foil. The key element of the new scheme is an additional foil that reflects the drive laser pulse, but lets the electrons pass almost unperturbed. It is shown by analytic theory and by 2D-PIC simulation that the electrons, after interacting with both drive and reflected laser pulse, form a very uniform flyer freely cruising with high relativistic gamma-factor exactly in drive laser direction (no transverse momentum). It backscatters probe light with a full Doppler shift factor of 4*gamma^2. The reflectivity and its decay due to layer expansion is discussed.