Near-field scanning optical microscopy is a powerful technique for imaging below the diffraction limit, which has been extensively used in biomedical imaging and nanophotonics. However, when the electromagnetic fields under measurement are strongly confined, they can be heavily perturbed by the presence of the near-field probe itself. Here, taking inspiration from scattering-cancellation invisibility cloaks, Huygens–Kerker scatterers, and cloaked sensors, we design and fabricate a cloaked near-field probe. We show that, by suitably nanostructuring the probe, its electric and magnetic polarizabilities can be controlled and balanced. As a result, probe-induced perturbations can be largely suppressed, effectively cloaking the near-field probe without preventing its ability to measure. We experimentally demonstrate the cloaking effect by comparing the interaction of conventional and nanostructured probes with a representative nanophotonic structure, namely, a 1D photonic-crystal cavity. Our results show that, by engineering the structure of the probe, one can systematically control its back action on the resonant fields of the sample and decrease the perturbation by {\gt}70\%${\gt}70\%$ with most of our modified probes, and by up to 1 order of magnitude for the best probe, at probe-sample distances of 100 nm. Our work paves the way for non-invasive near-field optical microscopy of classical and quantum nanosystems.

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用于非侵入式近场光学显微镜的隐形近场探头

近场扫描光学显微镜是一种在衍射极限以下成像的强大技术，已广泛用于生物医学成像和纳米光子学。然而，当测量的电磁场受到强烈限制时，它们可能会受到近场探头本身的严重干扰。在这里，我们从散射消除隐形斗篷、惠更斯-克尔克散射体和隐形传感器中汲取灵感，设计并制造了一个隐形近场探测器。我们表明，通过适当地纳米结构化探针，可以控制和平衡其电和磁极化率。因此，探针引起的扰动可以在很大程度上得到抑制，有效地掩盖近场探针，而不会妨碍其测量能力。我们通过比较常规和纳米结构探针与代表性纳米光子结构（即一维光子晶体腔）的相互作用，通过实验证明了隐形效应。我们的结果表明，通过设计探针的结构，可以系统地控制其对样品共振场的反作用，并通过以下方式减少扰动{\gt}70\%${\gt}70\%$与我们修改的大多数探针相比，在探针-样本距离为 100 nm 时，最佳探针最多提高 1 个数量级。我们的工作为经典和量子纳米系统的非侵入性近场光学显微镜铺平了道路。