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arXiv 2401.07686physics.optics
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金纳米颗粒单二聚体中的声学模式杂化

Acoustic Mode Hybridization in a Single Dimer of Gold Nanoparticles

Adrien Girard, Hélène Gehan, Alain Mermet, Jean Lermé, Alice Berthelot, Emmanuel Cottancin, Aurelien Crut, Jeremie Margueritat, Christophe Bonnet

AI总结:

该研究首次对单个金纳米颗粒单体和二聚体进行超低频微拉曼散射测量,揭示了二聚体中由聚合物介导的力学耦合导致的振动模式杂化及四极模式频移,并通过有限元模拟验证了实验结果,为纳米尺度振动研究提供了新方法。

摘要:

通过首次测量单个金纳米颗粒单体和二聚体的超低频微拉曼散射,研究了它们的声学振动。该实验不仅能够获得所检测振动模式的频率,还能获得其阻尼率,而在纳米物体集合体的测量中,阻尼率会被非均匀效应所掩盖。这使得能够对二聚体情形下两个紧密相邻的纳米颗粒之间(由周围聚合物介导)发生的力学耦合进行详细分析。这种耦合诱导了每个纳米颗粒振动模式的杂化,导致拉曼光谱中出现两个超低频模式,分别对应于纳米颗粒相对于二聚体轴的异相纵向和横向准平移。此外,研究还表明这种耦合会使纳米颗粒的四极模式频率发生偏移。实验结果利用有限元模拟进行了解释,这些模拟能够明确识别所检测到的模式,并且尽管做了简化,仍能合理地再现其测量频率和品质因子。所展示的在单个纳米物体上进行低频拉曼散射实验的可行性,为加深对纳米尺度振动的理解开辟了新的可能性,该技术与单个纳米物体时间分辨光谱学互补,因为它能够获取不同的振动模式。

英文摘要:

The acoustic vibrations of single monomers and dimers of gold nanoparticles were investigated by measuring for the first time their ultra-low frequency micro-Raman scattering. This experiment provides access not only to the frequency of the detected vibrational modes, but also to their damping rate, which is obscured by inhomogeneous effects in measurements on ensembles of nano-objects. This allows a detailed analysis of the mechanical coupling occurring between two close nanoparticles (mediated by the polymer surrounding them) in the dimer case. Such coupling induces the hybridization of the vibrational modes of each nanoparticle, leading to the appearance in the Raman spectra of two ultra-low frequency modes corresponding to the out-of-phase longitudinal and transverse (with respect to the dimer axis) quasi-translations of the nanoparticles. Additionally, it is also shown to shift the frequency of the quadrupolar modes of the nanoparticles. Experimental results are interpreted using finite-element simulations, which enable the unambiguous identification of the detected modes and, despite the simplifications made, lead to a reasonable reproduction of their measured frequencies and quality factors. The demonstrated feasibility of low frequency Raman scattering experiments on single nano-objects opens up new possibilities to improve the understanding of nanoscale vibrations, this technique being complementary with single nano-object time-resolved spectroscopy as it gives access to different vibrational modes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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