近日，德国马普量子光学研究所的Vladislav S.Yakovlev及其领导的研究小组取得一项新进展。经过不懈努力，他们探究了1飞秒尺度光注入后固体的动力学光学响应。相关研究成果已于2023年5月24日在国际权威学术期刊《自然》上发表。

该研究采用光学测量技术来研究载流子的动力学过程，并重点观察了在近1飞秒时间尺度内注入载流子后硅和二氧化硅的光学性质的演化。研究人员直接观察到了在最初几飞秒内形成的Drude-Lorentz响应，这一时间段远短于逆等离子频率。与之前在太赫兹领域的测量结果相比，这一发现对于推动基于电子的信号处理的发展至关重要。

据了解，光注入载流子极大地改变了固体的性质，为实现超快速测量提供了新的可能性。其中一种应用是电场采样，在最新的研究中已经将其发展到飞赫兹频率，并用于实时研究多体物理现象。通过利用几周期激光脉冲的非线性光激发，研究人员能够将测量限制在最强半个周期内。在阿秒量级光电子学中，准确描述与亚周期光学响应相关的现象至关重要。然而，当使用传统的泵浦-探测测量方法研究载流子的动力学过程时，描述变得困难，因为这些动力学会在载流子尺度上扭曲任何探测场，而不仅仅是影响其包络。

附：英文原文

Title: Dynamic optical response of solids following 1-fs-scale photoinjection

Author: Zimin, Dmitry A., Karpowicz, Nicholas, Qasim, Muhammad, Weidman, Matthew, Krausz, Ferenc, Yakovlev, Vladislav S.

Issue&Volume: 2023-05-24

Abstract: Photoinjection of charge carriers profoundly changes the properties of a solid. This manipulation enables ultrafast measurements, such as electric-field sampling^1,2, advanced recently to petahertz frequencies^3,4,5,6,7, and the real-time study of many-body physics^{8,9,10,11,12,13}. Nonlinear photoexcitation by a few-cycle laser pulse can be confined to its strongest half-cycle^14,15,16. Describing the associated subcycle optical response, vital for attosecond-scale optoelectronics, is elusive when studied with traditional pump-probe metrology as the dynamics distort any probing field on the timescale of the carrier, rather than that of the envelope. Here we apply field-resolved optical metrology to these dynamics and report the direct observation of the evolving optical properties of silicon and silica during the first few femtoseconds following a near-1-fs carrier injection. We observe that the Drude–Lorentz response forms within several femtoseconds—a time interval much shorter than the inverse plasma frequency. This is in contrast to previous measurements in the terahertz domain^8,9 and central to the quest to speed up electron-based signal processing.

DOI: 10.1038/s41586-023-05986-w

Source: https://www.nature.com/articles/s41586-023-05986-w