Optical forces on nanostructures are usually characterized by their interaction with the electric field component of the light wave, given that most materials present negligible magnetic response at optical frequencies. This is not the case however of a high-refractive-index dielectric nanoantenna, which has been recently shown to efficiently support both electric and magnetic optical modes. In this work, we use a photoinduced force microscopy configuration to measure optically induced forces produced by a germanium nanoantenna on a surrounding silicon near-field probe. We reveal the spatial distribution, character, and magnitude of the generated forces when exciting the nanoantenna at its anapole state condition. We retrieve optical force maps showing values of up to 20 pN, which are found to be mainly magnetic in nature, according to our numerical simulations. The results of this investigation open new pathways for the study, detection, and generation of magnetic light forces at the nanometer scale.

中文翻译：

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直接检测介电纳米天线中磁性的光学力。

鉴于大多数材料在光频率下呈现的磁响应可忽略不计，因此纳米结构上的光力通常以其与光波电场分量的相互作用为特征。但是，高折射率介电纳米天线却不是这种情况，近来已证明高折射率介电纳米天线可有效支持电和磁光学模式。在这项工作中，我们使用光感应力显微镜配置来测量由锗纳米天线在周围的硅近场探针上产生的光感应力。我们揭示了在其偶极状态条件下激发纳米天线时所产生力的空间分布，特征和大小。我们检索到的光学力图显示了高达20 pN的值，这些值本质上主要是磁性的，根据我们的数值模拟。这项研究的结果为研究，检测和产生纳米尺度的电磁力开辟了新的途径。