发表机构
Universidad de Buenos Aires; CONICET-Universidad de Buenos Aires; Ludwig-Maximilians-Universität München（布宜诺斯艾利斯大学; 阿根廷国家科学与技术研究理事会-布宜诺斯艾利斯大学; 慕尼黑路德维希-马克西米利安大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过双色泵浦-探测光谱和模拟，探究金纳米盘超表面中晶格间距对光学与机械耦合的调控，发现瑞利异常调谐及多种机械模式的不同响应。
AI 中文摘要
相邻等离激元纳米粒子之间的相互作用可以改变其固有的光学和机械共振，从而使得集体响应能够通过其排列的几何结构进行控制。因此，周期性阵列提供了一种通过共同的几何参数——晶格间距——来控制电磁和机械相互作用的手段。对这两个通道的联合控制对于设计相干机械激发如何耦合到衬底并在纳米尺度上进行光学读出尤为有用。在此，我们利用双色泵浦-探测光谱和数值模拟，研究了二氧化硅上金纳米盘超表面补丁的光学和机械响应随晶格间距的变化。在光学方面，模拟表明，改变间距会使瑞利异常在纳米盘的宽局域表面等离激元共振范围内调谐，从而产生强烈不对称的集体光学响应。泵浦-探测测量进一步揭示了相干机械振动的光学读出具有显著的波长依赖性。在机械方面，我们研究了纳米盘与衬底之间的耦合如何依赖于纳米盘共振的特性。固有的纳米盘模式对周期性环境表现出显著不同的敏感性。其中一种模式几乎与间距无关，而另一种模式则经历由通过衬底的弹性相互作用介导的显著频率偏移。数值模拟进一步揭示，第三种纳米盘共振与晶格选择的声学模式发生共振耦合，导致避免交叉和模式杂化。这些不同的机械响应由每种模式耦合到衬底近表面弹性运动的效率所决定。
英文摘要
The interaction between neighboring plasmonic nanoparticles can modify their intrinsic optical and mechanical resonances, enabling collective responses to be controlled through the geometry of their arrangement. Periodic arrays therefore provide a means of controlling both electromagnetic and mechanical interactions through a common geometrical parameter, the lattice pitch. Joint control of these two channels is particularly useful for engineering how coherent mechanical excitations couple to the substrate and are optically read out at the nanoscale. Here, we investigate the optical and mechanical response of gold nanodisk metasurface patches on silica as a function of lattice pitch using two-color pump-probe spectroscopy and numerical simulations. Optically, simulations show that varying the pitch tunes a Rayleigh anomaly across the broad localized surface plasmon resonance of the nanodisks, producing a strongly asymmetric collective optical response. Pump-probe measurements further reveal a pronounced wavelength dependence of the optical readout of coherent mechanical vibrations. Mechanically, we investigate how coupling between the nanodisks and the substrate depends on the character of the nanodisk resonances. The intrinsic nanodisk modes exhibit markedly different sensitivities to the periodic environment. One remains nearly independent of pitch, whereas another undergoes a pronounced frequency shift mediated by elastic interactions through the substrate. Numerical simulations further reveal that a third nanodisk resonance couples resonantly to a lattice-selected acoustic mode, giving rise to an avoided crossing and mode hybridization. These distinct mechanical responses are governed by how efficiently each mode couples to near-surface elastic motion in the substrate
