Wavelength-Dependent Photothermal Imaging Probes Nanoscale Temperature Differences among Subdiffraction Coupled Plasmonic Nanorods
Wavelength-Dependent Photothermal Imaging Probes Nanoscale Temperature Differences among Subdiffraction Coupled Plasmonic Nanorods
复制标题
波长相关光热成像探针亚衍射耦合等离子体纳米棒之间的纳米级温度差异
DOI：
10.1021/acs.nanolett.1c01740
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发表时间：
2021
期刊：
影响因子：
10.8
通讯作者：
Masiello, David J.
中科院分区：
文献类型：
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作者：
Hosseini Jebeli, Seyyed Ali;West, Claire A.;Lee, Stephen A.;Goldwyn, Harrison J.;Bilchak, Connor R.;Fakhraai, Zahra;Willets, Katherine A.;Link, Stephan;Masiello, David J.
等离子体结构将电磁能量限制在纳米级，导致局部、不均匀、可控的加热，但是使用光学技术读取温度是一个困难的挑战。在这里，我们报告了单个金纳米棒三聚体的光学测温，这些三聚体表现出多种波长相关的等离子体模式，导致可测量的不同局部温度分布。具体来说，我们演示了光热显微镜如何在光热图像点扩散函数的不对称性中编码不同波长相关的温度分布。这些不对称性通过伴随的数值模拟来解释，揭示了如何通过激发其杂化等离子体模式来控制三聚体内的热梯度。我们还发现，光学暗的等离子体模式可以通过聚焦激光束照明激发，这为修改宽场照明以外的热剖面提供了另一种途径。综上所述，这些发现证明了一种全光学测温技术可以积极地创建和测量低于衍射极限的纳米级热梯度。
Plasmonic structures confine electromagnetic energy at the nanoscale, resulting in local, inhomogeneous, controllable heating, but reading out the temperature using optical techniques poses a difficult challenge. Here, we report on the optical thermometry of individual gold nanorod trimers that exhibit multiple wavelength-dependent plasmon modes resulting in measurably different local temperature distributions. Specifically, we demonstrate how photothermal microscopy encodes different wavelength-dependent temperature profiles in the asymmetry of the photothermal image point spread function. These asymmetries are interpreted through companion numerical simulations to reveal how thermal gradients within the trimer can be controlled by exciting its hybridized plasmon modes. We also find that plasmon modes that are optically dark can be excited by focused laser beam illumination, providing another route to modify thermal profiles beyond wide-field illumination. Taken together these findings demonstrate an all-optical thermometry technique to actively create and measure nanoscale thermal gradients below the diffraction limit.