Division of Applied Physics, Graduate School of Engineering, Hokkaido University , Sapporo 060-8628, Japan.
Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology , Hawthorn, VIC 3122, Australia.
Nano Lett. 2017 Nov 8;17(11):6684-6689. doi: 10.1021/acs.nanolett.7b02663. Epub 2017 Oct 5.
Using polarization-resolved transient reflection spectroscopy, we investigate a metasurface consisting of coherently vibrating nanophotonic U-shaped split-ring meta-atoms that exhibit colocalized optical and mechanical resonances. With an array of these resonators formed of gold on glass, essentially miniature tuning forks, we monitor the visible-pump induced gigahertz oscillations in reflected infrared light intensity to probe the multimodal vibrational response. Numerical simulations of the associated transient deformations and strain fields elucidate the complex nanomechanical dynamics contributing to the ultrafast optical modulation and point to the role of acousto-plasmonic interactions through the opening and closing motion of the SRR gaps as the dominant effect. Applications include ultrafast acoustooptic modulator design and sensing.
我们使用偏振分辨瞬态反射光谱研究了一个由相干振动的纳米光子 U 型分裂环超材料单元组成的超表面，这些单元表现出了共定位的光学和机械共振。通过在玻璃上形成金制成的这种共振器阵列，即微型音叉，我们监测了可见泵浦诱导的反射红外光强度中的千兆赫振荡，以探测多模态振动响应。相关瞬态变形和应变场的数值模拟阐明了超快光调制的复杂纳米力学动力学，并指出了通过 SRR 间隙的开启和关闭运动产生的声 - 等离子体相互作用的作用，这是主要效应。应用包括超快声光调制器设计和传感。
