2023-05-24 ミュンヘン大学（LMU）
◆光注入による電子の自由化は、光子のエネルギーが制約を解放するポテンシャルよりも高い場合に起こります。また、非線形プロセスである多光子吸収や量子トンネリングも光注入を通じて発生することが分かりました。これにより、光駆動電流の制御や将来の光波エレクトロニクスの実現に向けた新たな知見が得られました。
＜関連情報＞
- https://www.lmu.de/en/newsroom/news-overview/news/snapshots-of-photoinjection.html
- https://www.nature.com/articles/s41586-023-05986-w
1fsスケールの光入射による固体の動的な光学応答 Dynamic optical response of solids following 1-fs-scale photoinjection
Dmitry A. Zimin,Nicholas Karpowicz,Muhammad Qasim,Matthew Weidman,Ferenc Krausz & Vladislav S. Yakovlev
Nature Published:24 May 2023
DOI:https://doi.org/10.1038/s41586-023-05986-w
Abstract
Photoinjection of charge carriers profoundly changes the properties of a solid. This manipulation enables ultrafast measurements, such as electric-field sampling1,2, advanced recently to petahertz frequencies3,4,5,6,7, and the real-time study of many-body physics8,9,10,11,12,13. Nonlinear photoexcitation by a few-cycle laser pulse can be confined to its strongest half-cycle14,15,16. 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 domain8,9 and central to the quest to speed up electron-based signal processing.
