Ionization-Induced Subcycle Metallization of Nanoparticles in Few-Cycle Pulses
Ionization-Induced Subcycle Metallization of Nanoparticles in Few-Cycle Pulses
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DOI：
10.1021/acsphotonics.0c01282
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发表时间：
2020-11-18
期刊：
影响因子：
7
通讯作者：
Kling, Matthias F.
中科院分区：
文献类型：
--
作者：
Liu, Qingcao;Seiffert, Lennart;Kling, Matthias F.
纳米级目标中的强场激光与物质相互作用为极端条件下物质的生成和详细表征提供了独特的途径。强激光场中纳米级固体的场驱动、亚周期电离诱导金属化已被预测（Peltz et al. Time-Resolved X-ray Imaging of Anisotropic Nanoplasma Expansion. Phys. Rev. Lett. 2014, 113, 133401），但其观测因缺乏确凿证据而受到阻碍。在这里，我们报告了在强烈的少周期激光脉冲下分离的电介质和半导体纳米颗粒的超快金属化。最高能量的电子发射被认为是一个决定性的证据，表明强度足以点燃颗粒体积中的载流子雪崩时，对金属极限的特征截止修改。半经典平均场米蒙特卡罗输运模拟揭示了潜在的动力学，并解释了通过来自金属化靶的近场驱动电子反向散射观察到的演化。
Strong-field laser-matter interactions in nanoscale targets offer unique avenues for the generation and detailed characterization of matter under extreme conditions. Field-driven, subcycle ionization-induced metallization of nanoscale solids in intense laser fields has been predicted (Peltz et al. Time-Resolved X-ray Imaging of Anisotropic Nanoplasma Expansion. Phys. Rev. Lett. 2014, 113, 133401), but its observation was hampered by a lack of a smoking gun. Here, we report the ultrafast metallization of isolated dielectric and semiconducting nanoparticles under intense few-cycle laser pulses. The highest-energy electron emission is found to be a decisive proof that shows a characteristic cutoff modification to a metallic limit for intensities high enough to ignite carrier avalanching in the volume of the particles. Semiclassical Mean-field Mie Monte-Carlo transport simulations reveal the underlying dynamics and explain the observed evolution by near-field driven electron backscattering from the metallizing target.