Yao Jiacheng, Wang Cheng, Zhang Chi, Ma Song, Zhou Li, Wang Ti, Wang Ququan, Xu Hongxing, Ding Tao
Key Laboratory of Artificial Micro/Nano Structure of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China.
Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China.
Natl Sci Rev. 2023 Nov 3;11(5):nwad280. doi: 10.1093/nsr/nwad280. eCollection 2024 May.
Fast optical modulation of nanoplasmonics is fundamental for on-chip integration of all-optical devices. Although various strategies have been proposed for dynamic modulation of surface plasmons, critical issues of device compatibility and extremely low efficiency in the visible spectrum hamper the application of optoplasmonic nanochips. Here we establish an optoplasmonic system based on Au@CuS hybrid core-shell nanoparticles. The optical excitation of hot electrons and their charge transfer to the semiconductor coating (CuS) lead to lowered electron density of Au, which results in the red shift of the localized surface plasmon resonance. The hot electrons can also transport through the CuS layer to the metal substrate, which increases the conductance of the nanogap. As such, the coupled gap plasmon blue-shifts with a magnitude of up to ∼15 nm, depending on the excitation power and the thickness of the coatings, which agrees with numerical simulations. All of this optoelectronic tuning process is highly reversible, controllable and fast with a modulated laser beam, which is highly compatible and sufficiently useful for on-chip integration of nanophotonic devices.
纳米等离子体的快速光学调制对于全光器件的片上集成至关重要。尽管已经提出了各种用于表面等离子体动态调制的策略，但器件兼容性的关键问题以及在可见光谱中极低的效率阻碍了光等离子体纳米芯片的应用。在此，我们基于金@硫化铜混合核壳纳米颗粒建立了一个光等离子体系统。热电子的光激发及其向半导体涂层（硫化铜）的电荷转移导致金的电子密度降低，这导致局域表面等离子体共振发生红移。热电子还可以通过硫化铜层传输到金属基底，这增加了纳米间隙的电导。因此，耦合间隙等离子体蓝移，幅度高达约15纳米，这取决于激发功率和涂层厚度，与数值模拟结果一致。所有这些光电调谐过程都具有高度的可逆性、可控性，并且通过调制激光束可以快速实现，这对于纳米光子器件的片上集成具有高度兼容性且非常有用。
