Plasma and Fusion Research

Volume 20, 2406013 (2025)

Regular Articles


EUV Emission from a Regenerative Liquid Target Laser-Produced Plasma
Tatsuya SORAMOTO1), Takeru NIINUMA1), Hiroki MORITA1), Shinichi NAMBA2) and Takeshi HIGASHIGUCHI1)
1)
Department of Electrical and Electronic Engineering, Utsunomiya University, Utsunomiya 321-8585, Japan
2)
Department of Advanced Science and Engineering, Hiroshima University, Higashihiroshima 739-8527, Japan
(Received 15 July 2024 / Accepted 23 October 2024 / Published 22 January 2025)

Abstract

We demonstrated the efficient water-window extreme ultraviolet (EUV) source using a regenerative liquid metal target irradiated by a 10-Hz, 150-ps, solid-state laser at a wavelength of 1.064 µm. A regenerative liquid bismuth (Bi) target with a diameter of 30 µm was continuously injected into a vacuum. The number of photons was about 1 × 1013 photons/(sr · shot) in the spectral region from 2.3 to 4.4 nm, which was attributed to be n = 4 – n = 4 (Δn = 0) and n = 4 – n = 5 (Δn = 1) transitions. The fast ion was also observed with a maximum energy of 140 keV from a hot, dense Bi plasma.


Keywords

laser-produced plasma, soft x-ray, water window, highly charged ion (HCI), bismuth

DOI: 10.1585/pfr.20.2406013


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