Wong Kai-Fu, Li Weiwei, Wang Zilong, Wanie Vincent, Månsson Erik, Hoeing Dominik, Blöchl Johannes, Nubbemeyer Thomas, Azzeer Abdallah, Trabattoni Andrea, Lange Holger, Calegari Francesca, Kling Matthias F
The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
Nano Lett. 2024 May 8;24(18):5506-5512. doi: 10.1021/acs.nanolett.4c00658. Epub 2024 Mar 26.
The response of metal nanostructures to optical excitation leads to localized surface plasmon (LSP) generation with nanoscale field confinement driving applications in, for example, quantum optics and nanophotonics. Field sampling in the terahertz domain has had a tremendous impact on the ability to trace such collective excitations. Here, we extend such capabilities and introduce direct sampling of LSPs in a more relevant petahertz domain. The method allows to measure the LSP field in arbitrary nanostructures with subcycle precision. We demonstrate the technique for colloidal nanoparticles and compare the results to finite-difference time-domain calculations, which show that the build-up and dephasing of the plasmonic excitation can be resolved. Furthermore, we observe a reshaping of the spectral phase of the few-cycle pulse, and we demonstrate ad-hoc pulse shaping by tailoring the plasmonic sample. The methodology can be extended to single nanosystems and applied in exploring subcycle, attosecond phenomena.
金属纳米结构对光激发的响应会导致局域表面等离子体（LSP）的产生，其具有纳米级的场限制，推动了在量子光学和纳米光子学等领域的应用。太赫兹领域的场采样对追踪此类集体激发的能力产生了巨大影响。在此，我们扩展了这种能力，并引入了在更相关的拍赫兹领域对LSP进行直接采样。该方法能够以亚周期精度测量任意纳米结构中的LSP场。我们展示了针对胶体纳米颗粒的技术，并将结果与有限时域差分计算进行比较，结果表明等离子体激发的形成和退相能够被解析。此外，我们观察到少周期脉冲的光谱相位发生了重塑，并且通过定制等离子体样品展示了即时光脉冲整形。该方法可以扩展到单个纳米系统，并应用于探索亚周期、阿秒现象。
