Polarized Nonlinear Nanoscopy of Metal Nanostructures
Polarized Nonlinear Nanoscopy of Metal Nanostructures
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DOI：
10.1021/acsphotonics.6b00635
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发表时间：
2017-02-01
期刊：
影响因子：
7
通讯作者：
Brasselet, Sophie
中科院分区：
文献类型：
--
作者：
Balla, Naveen Kumar;Rendon-Barraza, Carolina;Brasselet, Sophie
由于非线性光学耦合的固有矢量性质，来自金属纳米结构的非线性信号已知是高度偏振依赖的。非线性光学偏振响应包含纳米结构的近场特性的重要信息，然而，它们在纳米尺度上的监测和建模仍然很复杂。偏振分辨非线性光学显微镜可以潜在地解决这个问题;然而，记录的信号通常在几百纳米的衍射极限尺寸上被平均，因此，错过了纳米结构的光学响应的空间特异性。在这里，我们提出了一种形式的偏振分辨显微镜，命名为偏振非线性纳米显微镜，它揭示了subdiffraction尺度的矢量变化的电磁场，即使强度图像是衍射限制。我们表明，通过利用，在一个单一的subdiffraction像素水平，所获得的信息的偏振诱导调制，它是可能的空间映射的矢量性质的等离子体非线性光学相互作用的纳米结构，揭示特别是表面的贡献，延迟效应，和各向异性的空间限制。
Nonlinear signals from metal nanostructures are known to be highly polarization-dependent, due to the intrinsic vectorial nature of nonlinear optical coupling. Nonlinear optical polarization responses contain important information on the near-field properties of nanostructures;, however, they remain complex to monitor and to model at the nanoscale. Polarization resolved nonlinear optical microscopy can potentially address this question; however, the recorded signals are generally averaged over the diffraction-limited size of a few hundreds of nanometers, thus, missing the spatial specificity of the nanostructure's optical response. Here we present a form of polarization resolved microscopy, named polarization nonlinear nanoscopy, which reveals subdiffraction scale vectorial variations of electromagnetic fields, even though the intensity image is diffraction-limited. We show that by exploiting, at a single subdiffraction pixel level, the information gained by the polarization-induced modulation, it is possible to spatially map the vectorial nature of plasmonic nonlinear optical interactions in nanostructures, revealing in particular surface contributions, retardation effects, and anisotropic spatial confinements.