Gamma ray vortices from nonlinear inverse Compton scattering of circularly polarized light

TL;DR

This paper theoretically demonstrates that gamma rays produced via nonlinear inverse Compton scattering of circularly polarized light are vortex beams carrying orbital angular momentum, with implications for astrophysics and gamma ray science.

Contribution

It reveals that nonlinear inverse Compton scattering generates gamma ray vortices with helical wave fronts, explaining recent experimental observations and proposing a new gamma ray vortex source.

Findings

Gamma ray vortices possess helical wave fronts.

Nonlinear ICS produces gamma ray vortices with orbital angular momentum.

Potential applications in astrophysics and gamma ray science.

Abstract

Inverse Compton scattering (ICS) is an elemental radiation process that produces high-energy photons both in nature and in the laboratory. Non-linear ICS is a process in which multiple photons are converted to a single high-energy photon. Here, we theoretically show that the photon produced by non-linear ICS of circularly polarized photons is a vortex, which means that it possesses a helical wave front and carries orbital angular momentum. Our work explains a recent experimental result regarding non-linear Compton scattering that clearly shows an annular intensity distribution as a remarkable feature of a vortex beam. Our work implies that gamma ray vortices should be produced in various situations in astrophysics in which high-energy electrons and intense circularly polarized light fields coexist. They should play a critical role in stellar nucleosynthesis. Non-linear ICS is the most promising radiation process for realizing a gamma ray vortex source based on currently available laser and accelerator technologies, which would be an indispensable tool for exploring gamma ray vortex science.