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Laser prepulse-induced deformation dynamics in tin microdroplets for extreme ultraviolet light source applications

Qi Min1,2,*, Chaowei He1, Haidong Lu1, Xingbang Liu1, Maogen Su1,2,†, and Chenzhong Dong1,2,‡

  • 1Key Laboratory of Atomic and Molecular Physics & Functional Material of Gansu Province, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
  • 2Gansu International Scientific and Technological Cooperation Base of Laser Plasma Spectroscopy, Lanzhou 730070, China

  • *Contact author: mq_lpps@nwnu.edu.cn
  • †Contact author: sumg@nwnu.edu.cn
  • ‡Contact author: dongcz@nwnu.edu.cn
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Phys. Rev. Research 7, 043155 – Published 12 November, 2025

DOI: https://doi.org/10.1103/3v34-2f14

Abstract

This paper presents a detailed numerical investigation of the deformation dynamics of spherical tin (Sn) microdroplets under the action of laser prepulses, which is an essential process for optimizing extreme ultraviolet (EUV) lithography targets. A hybrid simulation method is developed, combining a single-fluid radiation hydrodynamics model for laser-produced plasmas with a two-phase flow model that incorporates surface tension effects. Two distinct scenarios are analyzed using this hybrid approach: nanosecond and picosecond prepulses, each characterized by markedly different energy deposition and deformation mechanisms. The simulations capture the full deformation process from initial laser impact to the capillary timescale, reproducing target morphologies that show good agreement with experimental observations. Detailed quantitative analyses of droplet expansion rates and geometries are also provided. Finally, the impact of the predeformed targets on EUV emission performance is evaluated by simulating the interaction of a CO2 main pulse with the deformed structures. This study offers significant insights into laser-droplet interactions and contributes to the development of precise control strategies for optimizing EUV target shaping.

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Phys. Rev. Research 7, 043155– Published 12 November, 2025
  • Received 27 April 2025
  • Accepted 19 October 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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