Department of Physics and London Centre for Nanotechnology, King's College London, London WS2R 2LS, U.K.
Nano Lett. 2023 Apr 12;23(7):2786-2791. doi: 10.1021/acs.nanolett.3c00063. Epub 2023 Mar 16.
The optically driven acoustic modes and nonlinear response of plasmonic nanoparticles are important in many applications, but are strongly resonant, which restricts their excitation to predefined wavelengths. Here, we demonstrate that multilayered spherical plasmonic hetero-nanoparticles, formed by alternating layers of gold and silica, provide a platform for a broadband nonlinear optical response from visible to near-infrared wavelengths. They also act as a tunable optomechanical system with mechanically decoupled layers in which different acoustic modes can be selectively switched on/off by tuning the excitation wavelength. These observations not only expand the knowledge about the internal structure of composite plasmonic nanoparticles but also allow for an additional degree of freedom for controlling their nonlinear optical and mechanical properties.
光驱动的声模式和等离子体纳米粒子的非线性响应在许多应用中都很重要，但它们的共振很强，这限制了它们的激发只能在预定的波长范围内进行。在这里，我们证明了由金和二氧化硅交替层形成的多层球形等离子体杂化纳米粒子为从可见光到近红外波长的宽带非线性光学响应提供了一个平台。它们还充当可调谐的光机械系统，其中机械上解耦的层可以通过调谐激发波长来选择性地打开/关闭不同的声模式。这些观察结果不仅扩展了关于复合等离子体纳米粒子的内部结构的知识，而且为控制其非线性光学和机械性能提供了额外的自由度。
