Determining the duration of an ultra-intense laser pulse directly in its focus

Felix Mackenroth,Amol R Holkundkar

doi:10.1038/s41598-019-55949-3

Abstract

Ultra-intense lasers facilitate studies of matter and particle dynamics at unprecedented electromagnetic field strengths. In order to quantify these studies, precise knowledge of the laser’s spatiotemporal shape is required. Due to material damage, however, conventional metrology devices are inapplicable at highest intensities, limiting laser metrology there to indirect schemes at attenuated intensities. Direct metrology, capable of benchmarking these methods, thus far only provides static properties of short-pulsed lasers with no scheme suggested to extract dynamical laser properties. Most notably, this leaves an ultra-intense laser pulse’s duration in its focus unknown at full intensity. Here we demonstrate how the electromagnetic radiation pattern emitted by an electron bunch with a temporal energy chirp colliding with the laser pulse depends on the laser’s pulse duration. This could eventually facilitate to determine the pulse’s temporal duration directly in its focus at full intensity, in an example case to an accuracy of order 10% for fs-pulses, indicating the possibility of an order-of magnitude estimation of this previously inaccessible parameter.

Highlights

Ultra-intense lasers facilitate studies of matter and particle dynamics at unprecedented electromagnetic field strengths
We show how an ultra-intense laser’s pulse duration can in principle be measured directly in its focus at ultra-high field strengths, providing an order-of-magnitude benchmark for conventional indirect pulse metrology
We have put forward a scheme capable of determining the duration of a laser pulse of in principle arbitrarily high intensity

Summary

Introduction

Ultra-intense lasers facilitate studies of matter and particle dynamics at unprecedented electromagnetic field strengths. One possible solution is quantifying the emission patterns of electrons scattered from the laser focus, giving access to a direct determination of its carrier-envelope phase[35,36] and intensity[18], with the latter already implemented experimentally[37] This latter experiment is in line with a series of recent experiments on laser-electron accelerators[38,39,40] and all-optical radiation sources[4,5,41,42,43], for which there exists an abundance of refined detectors for both the electrons and emitted radiation[44]. The pulse duration, a highly relevant pulse parameter, cannot be determined at full intensity by either solid state devices or the electron scattering schemes mentioned above, indicating the lack of a possibility to benchmark indirect pulse duration measurements in ultra-intense lasers’ foci at full intensity

Methods

Findings

Conclusion