Time-resolved x-ray imaging of a laser-induced nanoplasma and its neutral residuals

L Flückiger,C Bostedt,S Düsterer,T Möller,T Oelze,H Redlin,M Sauppe,D Rupp,T Gorkhover,M Krikunova,M Müller,M Harmand,M Adolph,S Schorb,Y Ovcharenko,R Treusch

doi:10.1088/1367-2630/18/4/043017

Abstract

The evolution of individual, large gas-phase xenon clusters, turned into a nanoplasma by a high power infrared laser pulse, is tracked from femtoseconds up to nanoseconds after laser excitation via coherent diffractive imaging, using ultra-short soft x-ray free electron laser pulses. A decline of scattering signal at high detection angles with increasing time delay indicates a softening of the cluster surface. Here we demonstrate, for the first time a representative speckle pattern of a new stage of cluster expansion for xenon clusters after a nanosecond irradiation. The analysis of the measured average speckle size and the envelope of the intensity distribution reveals a mean cluster size and length scale of internal density fluctuations. The measured diffraction patterns were reproduced by scattering simulations which assumed that the cluster expands with pronounced internal density fluctuations hundreds of picoseconds after excitation.

Highlights

Gas phase clusters are ideal systems to investigate the interaction between intensive light pulses and matter and in particular to follow the underlying processes of the formation and control of highly excited plasma states [1, 2]
The initial cluster state upon IR laser excitation cannot be directly extracted from the recorded images
It is assumed that these patterns result from the largest xenon clusters (700–1000 nm radius) in the size distribution intercepted at the central FEL focus position

Summary

13 April 2016

Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. L Flückiger1,2, D Rupp1, M Adolph1, T Gorkhover1,3, M Krikunova1, M Müller1, T Oelze1, Y Ovcharenko1,4, M Sauppe1, S Schorb1,3, C Bostedt3,5, S Düsterer6, M Harmand6,7, H Redlin6, R Treusch6 and T Möller1 Keywords: clusters, free-electron laser, pump–probe experiment, time-resolved imaging, nanoplasma Any further distribution of Supplementary material for this article is available online this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Introduction

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