Microsphere-lens coupler with 100 nm lateral resolution accuracy in visible light.

We propose a microsphere-lens coupler that can successfully constrain the beam with near-field details to achieve ∼100 lateral resolution accuracy. In theory, we use the finite-difference time-domain method to analyze the properties of the "photonic nanojet." The optimal focusing ability scope can be obtained by adjusting the focusing parameters, such as refractive index, paraxial optical intensity attenuation ratio, sizes of microspheres, and so forth. In experiment, the "non-brush scrubbing" cleaning technology is adopted to optimize the experimental results. Aiming to self-assemble properties of dielectric spheres, we introduce the deagglomeration method to produce homogeneous liquid. Meanwhile, by tiling a 5 µm-diameter microsphere-lens on a specimen, a traditional optical microscope can realize 100 nm lateral superresolution microimaging, which lays a certain foundation for further development of superresolution microimaging.