Theoretical Analysis of Hanbury Brown and Twiss Interferometry at Soft X-ray Free-Electron Lasers

TL;DR

This paper offers a theoretical framework for analyzing second-order correlation functions in soft X-ray free-electron laser experiments, considering the effects of monochromator resolution and beam properties.

Contribution

It provides a detailed theoretical analysis of beam propagation and correlation functions in soft X-ray FELs, including the impact of monochromator parameters and statistical beam properties.

Findings

Analysis of beam propagation through VLS monochromators

Connection of correlation functions with Gaussian Schell-model pulses

Insights into the interplay between monochromator resolution and beam statistics

Abstract

In this work we provide theoretical background for the analysis of second-order correlation functions in experiments performed at the soft x-ray free-electron lasers (XFELs). Typically, soft x-ray beamlines at XFELs are equipped by the variable line spacing (VLS) monochromators. We perform examination of the beam propagation through such VLS monochromator taking specially into account the interplay between the finite monochromator resolution and the exit slits width. We then provide general analysis of the second-order correlation intensities in spectral and spatial domains. Finally, we connect these functions with the statistical properties of the beam incoming to the monochromator unit in the limit of Gaussian Schell-model pulses.