Rare‐Earth Plasma Beyond Extreme Ultraviolet (BEUV) Sources at 6.x nm

Abstract

SUMMARYWe have studied self-absorption effects of a laserproduced plasma (LPP) source at 6.x nm as a function of laser pulse duration and viewing angle. The spectral profiles are shown to have a strong dependence on the viewing angle. Absorption effects are less pronounced when a 150-ps pulse duration is used due to reduced opacity resulting from plasma expansion. Conversion efficiencies and ion energies are also measured as a function of laser pulse duration and laser power density. A maximum conversion efficiency of 0.4% within a 0.6% bandwidth was measured, and lower ion kinetic energy was observed. It is concluded that in order to reduce self-absorption effects and ion yields, and increase conversion efficiencies, a short pulse duration should be used. C⃝ 2015 Wiley Periodicals, Inc. Electron Comm Jpn, 98(4): 52-58, 2015; Published online in Wiley Online Library (wileyonlinelibrary.com).

Investigation of a Collisional Radiative Model for Laser-Produced Plasmas

“…It would be expected that ionization bottlenecks should be observed at Sn 2+ , Sn 4+ and Sn 14+ . Examples of this discrepancy in other research can be seen in the ion distribution plots of Gd [8,26,27] and Sn [28].…”