Realising Single-Shot Measurements of Quantum Radiation Reaction in High-Intensity Lasers

TL;DR

This paper introduces a method to observe quantum radiation reaction effects in high-intensity laser-electron collisions within a single shot by using a pre-collision drift to correlate electron beam position and divergence.

Contribution

The study demonstrates a novel single-shot measurement technique that distinguishes electron beam components affected by radiation reaction through spatial and angular correlation.

Findings

Single-shot measurement of quantum radiation reaction achieved.

Pre-collision drift creates position-divergence correlation in electron beams.

Method enables clear identification of radiation reaction effects in a single laser shot.

Abstract

Collisions between high intensity laser pulses and energetic electron beams are now used to measure the transition between the classical and quantum regimes of light-matter interactions. However, the energy spectrum of laser-wakefield-accelerated electron beams can fluctuate significantly from shot to shot, making it difficult to clearly discern quantum effects in radiation reaction, for example. Here we show how this can be accomplished in only a single laser shot. A millimeter-scale pre-collision drift allows the electron beam to expand to a size larger than the laser focal spot and develop a correlation between transverse position and angular divergence. In contrast to previous studies, this means that a measurement of the beam's energy-divergence spectrum automatically distinguishes components of the beam that hit or miss the laser focal spot and therefore do and do not experience radiation reaction.