Reflection of intense laser light from microstructured targets as a potential diagnostic of laser focus and plasma temperature

Abstract

The spatial-intensity profile of light reflected during the interaction of an intense laser pulse with a microstructured target is investigated experimentally and the potential to apply this as a diagnostic of the interaction physics is explored numerically. Diffraction and speckle patterns are measured in the specularly reflected light in the cases of targets with regular groove and needle-like structures, respectively, highlighting the potential to use this as a diagnostic of the evolving plasma surface. It is shown, via ray-tracing and numerical modelling, that for a laser focal spot diameter smaller than the periodicity of the target structure, the reflected light patterns can potentially be used to diagnose the degree of plasma expansion, and by extension the local plasma temperature, at the focus of the intense laser light. The reflected patterns could also be used to diagnose the size of the laser focal spot during a high-intensity interaction when using a regular structure with known spacing.

Metadata

Authors/Creators:	Jarrett, J. King, M. Gray, R. J. Neumann, N. Döhl, L. Baird, C. D. Ebert, T. Hesse, M. Tebartz, A. Rusby, D. R. Woolsey, N. C. https://orcid.org/0000-0002-2444-9027 Neely, D. Roth, M. McKenna, P.
Copyright, Publisher and Additional Information:	© The Author(s) 2019. Funding Information: The authors acknowledge the expertise of the STFC Central Laser Facility staff and the Detector and Target Laboratory staff at the Institut fur Kernphysik, Technische Universitat Darmstadt. Simulations were performed using the EPOCH PIC code (developed under EPSRC grant number EP/G054940/1), running on the ARCHER high performance computer, with access provided via the EPSRC-funded Plasma Physics HEC Consortia (EP/L000237/1). This work is financially supported by EPSRC (grant numbers EP/R006202/1 and EP/K022415/1) and the European Union Horizon 2020 research and innovation programme under grant agreement number 654148 Laserlab-Europe. The data presented in this paper is available at http://dx.doi.org/10.15129/6805696a-13c1-4c56-a2db-d5eb5a471d33. Funding Information: The authors acknowledge the expertise of the STFC Central Laser Facility staff and the Detector and Target Laboratory staff at the Institut fur Kernphysik, Technische Universitat Darmstadt. Simulations were performed using the EPOCH PIC code (developed under EPSRC grant number EP/G054940/1), running on the ARCHER high performance computer, with access provided via the EPSRC-funded Plasma Physics HEC Consortia (EP/L000237/1). This work is financially supported by EPSRC (grant numbers EP/R006202/1 and EP/K022415/1) and the European Union Horizon 2020 research and innovation pro-gramme under grant agreement number 654148 Laserlab-Europe. The data presented in this paper is available at http://dx.doi.org/10.15129/6805696a-13c1-4c56-a2dbd5eb5a471d33. Publisher Copyright: © The Author(s) 2019.
Keywords:	High power laser, Laser-solid interactions, Plasma temperature diagnosis
Dates:	Accepted: 13 November 2018 Published (online): 27 December 2018 Published: 27 December 2018
Institution:	The University of York
Academic Units:	The University of York > Faculty of Sciences (York) > Chemistry (York) The University of York > Faculty of Sciences (York) > Biology (York) The University of York > Faculty of Sciences (York) > Physics (York)
Depositing User:	Pure (York)
Date Deposited:	24 Jan 2020 16:30
Last Modified:	06 Dec 2023 13:31
Published Version:	https://doi.org/10.1017/hpl.2018.63
Status:	Published
Refereed:	Yes
Identification Number:	https://doi.org/10.1017/hpl.2018.63
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