Wang Fei, Han Zexiang, Sun Juehan, Yang XueKang, Wang Xiaoli, Tang Zhiyong
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China.
Center of Materials Science and Optoelectronics Engineering, School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Mater. 2024 Feb;36(5):e2304657. doi: 10.1002/adma.202304657. Epub 2023 Dec 5.
Ultracompact chiral plasmonic nanostructures with unique chiral light-matter interactions are vital for future photonic technologies. However, previous studies are limited to reporting their steady-state performance, presenting a fundamental obstacle to the development of high-speed optical devices with polarization sensitivity. Here, a comprehensive analysis of ultrafast chiroptical response of chiral gold nano-oligomers using time-resolved polarimetric measurements is provided. Significant differences are observed in terms of the absorption intensity, thus hot electron generation, and hot carrier decay time upon polarized photopumping, which are explained by a phenomenological model of the helicity-resolved optical transitions. Moreover, the chiroptical signal is switchable by reversing the direction of the pump pulse, demonstrating the versatile modulation of polarization selection in a single device. The results offer fundamental insights into the helicity-resolved optical transitions in photoexcited chiral plasmonics and can facilitate the development of high-speed polarization-sensitive flat optics with potential applications in nanophotonics and quantum optics.
具有独特手性光与物质相互作用的超紧凑型手性等离子体纳米结构对未来光子技术至关重要。然而，先前的研究仅限于报告其稳态性能，这对具有偏振敏感性的高速光学器件的发展构成了根本障碍。在此，通过时间分辨偏振测量对手性金纳米低聚物的超快手性光学响应进行了全面分析。在偏振光泵浦时，观察到吸收强度、热电子产生以及热载流子衰减时间方面的显著差异，这些差异由螺旋度分辨光学跃迁的唯象模型解释。此外，通过反转泵浦脉冲方向可切换手性光学信号，证明了在单个器件中对偏振选择的多功能调制。这些结果为光激发手性等离子体中螺旋度分辨光学跃迁提供了基本见解，并有助于开发具有在纳米光子学和量子光学中潜在应用的高速偏振敏感平面光学器件。
