Controlling the spectrum of x-rays generated in a laser-plasma accelerator by tailoring the laser wavefront

TL;DR

This paper demonstrates that tailoring the laser wavefront in a laser-plasma accelerator allows control over the x-ray spectrum by increasing the electron beam's oscillation amplitude, notably enhancing the critical energy of emitted x-rays.

Contribution

It introduces a method to manipulate the x-ray spectrum in laser-wakefield accelerators through laser wavefront shaping, specifically using coma to increase the critical energy.

Findings

Coma wavefront increases the x-ray critical energy.

Wavefront shaping does not significantly alter electron beam energy.

Increased divergence and oscillation amplitude observed with coma.

Abstract

By tailoring the wavefront of the laser pulse used in a laser-wakefield accelerator, we show that the properties of the x-rays produced due to the electron beam's betatron oscillations in the plasma can be controlled. By creating a wavefront with coma, we find that the critical energy of the synchrotron-like x-ray spectrum can be significantly increased. The coma does not substantially change the energy of the electron beam, but does increase its divergence and produces an energy-dependent exit angle, indicating that changes in the x-ray spectrum are due to an increase in the electron beam's oscillation amplitude within the wakefield.