Spectral Bandwidth Reduction of Thomson Scattered Light by Pulse Chirping

TL;DR

This paper introduces a relativistic numerical code to analyze Thomson scattering, demonstrating that laser pulse chirping can effectively reduce spectral broadening caused by pulsed laser fields.

Contribution

A new fully relativistic 3D numerical code for Thomson scattering analysis that quantifies spectral broadening and shows how pulse chirping minimizes this effect.

Findings

Spectral broadening occurs due to laser pulse pulsed nature.

Chirping the laser pulse reduces spectral broadening.

Code validated against analytical plane wave models.

Abstract

Based on single particle tracking in the framework of classical Thomson scattering with incoherent superposition, we developed a fully relativistic, three dimensional numerical code that calculates and quantifies the characteristics of emitted radiation when a relativistic electron beam collides head-on with a focused counter-propagating intense laser field. The developed code has been benchmarked against analytical expressions, based on the plane wave approximation to the laser field, derived in (1). For sufficiently long duration laser pulses, we find that the scattered radiation spectrum is broadened due to interferences arising from the pulsed nature of the laser. We show that by appropriately chirping the scattering laser pulse, the spectral broadening could be minimized.