The ionization dynamics of Xe cluster was analyzed by extreme ultraviolet (EUV) pump-near infrared (NIR) probe experiments. The experiments were carried out for Xe clusters containing around 5000 atoms on average at the SPring-8 Compact SASE Source (SCSS) test accelerator in Japan. We recorded ion spectra emitted from Xe clusters as a function of the time delay between the EUV and NIR pulses. The ion yields up to highly-charged states were substantially enhanced when Xe clusters excited by the EUV pulses were illuminated by the NIR laser pulses at 1 to 2 ps after the pump pulse, providing a compelling evidence for nano-plasma formation and subsequent NIR absorption via surface plasma resonance. We also observed emergence of low kinetic energy Xe⁺ at long time delay, which can be attributed to the ionization of excited neutral atoms resulting from the electron-ion recombination in the expanding nano-plasma.

通过极紫外 (EUV) 泵-近红外 (NIR) 探针实验分析了氙团簇的电离动力学。这些实验是在日本的 SPring-8 Compact SASE Source (SCSS) 测试加速器上对平均包含约 5000 个原子的 Xe 簇进行的。我们记录了 Xe 簇发射的离子光谱作为 EUV 和 NIR 脉冲之间的时间延迟的函数。当在泵浦脉冲后 1 到 2 ps 用近红外激光脉冲照射由 EUV 脉冲激发的氙簇时，高达高电荷态的离子产率显着提高，为纳米等离子体形成和随后的近红外吸收提供了令人信服的证据通过表面等离子体共振。我们还观察到低动能 Xe ⁺ 长时间延迟，这可归因于膨胀的纳米等离子体中电子 - 离子复合导致激发的中性原子的电离。