Optical microscopy techniques have recently been shown to have the capability to exceed the diffraction limit when a microsphere is used. The mechanism involved in super-resolution imaging is theoretically analysed in this paper. A microsphere is also known to generate a photonic nanojet with a waist smaller than the diffraction limit. This nanojet is used as near-field illumination, and interacts with the sample to give a passive spatial frequency shift for the sample, meaning that near-field evanescent waves containing high-frequency spatial information about the sample can be converted into far-field propagating waves. This method is simple and cost-effective, and offers a promising approach for achieving far-field super-resolution imaging. Our theoretical analysis of super-resolution imaging is verified based on numerical and experimental results.

最近已证明，使用微球体时，光学显微镜技术具有超过衍射极限的能力。从理论上分析了超分辨率成像所涉及的机理。还已知微球产生腰部小于衍射极限的光子纳米射流。这种纳米射流被用作近场照明，并与样品相互作用，为样品提供被动的空间频移，这意味着包含有关样品的高频空间信息的近场e逝波可以转换为远场传播波浪。该方法简单且具有成本效益，为实现远场超分辨率成像提供了一种有前途的方法。