Fig. 1. Schematic diagram of evanescent wave coupled with microsphere lens ^[12]

Fig. 2. Schematic diagram of photon nanojet ^[15]

Fig. 3. (a) SEM image of an array of gold NPDs formed by 120 nm nanoparticles; Imaging effect and resolution analysis for different diameters D: (b) 4.2 μm, (c) 21.5 μm, and (d) 53 μm^[19]

Fig. 4. (a1) Soda lime glass microspheres imaging; (a2) Barium titanate glass microspheres imaging ^[20]; (b1), (b2) and (b3) are the virtual images of the 400 nm periodic object at Z positions of 30 μm, 55 μm and 90 μm, respectively. Scale bars represent 1 μm

Fig. 5. Schematic diagram of the immersion method of microspheres. (a) No immersion liquid ^[6]; (b) Half immersion ^[24]; (c) Full immersion ^[19]

Fig. 6. Super-resolution images produced by different immersion methods of microspheres. (a)-(d) No immersion liquid ^[6]; (e),(f) Half immersion ^[24]; (g),(h) Full immersion ^[19]

Fig. 7. Imaging effects of different objective lenses ^[20]. (a) SEM; (b) 20×(NA=0.4); (c) 100×(NA=0.9)

Fig. 8. Super-resolution imaging of a two-dimensional array of SNCs^[26]. (a) BFI; (b) DFI

Fig. 9. Schematic diagram and super-resolution images of mechanical strut devices. (a),(e) Capillary glass tube method ^[32]; (b),(f) Cantilever beam method ^[33]; (c),(g) ST-type tungsten probe method ^[34]; (d),(h) AFM probe method ^[36]

Fig. 10. (a) The BTG sphere is 40 μm away from the edge of an Au nanoplasmonic array; (b) The same sphere is at the border of array; (c) The dimers are seen near the array’s edge; (d) Diagram of experimental setup^[38]

Fig. 11. (a) Schematic illustration of swimming microrobot optical nanoscopy (SMON); (b) Schematic illustration of the chemically powered propulsion; (c) Schematic diagram of coating; (d) SEM image; (e) Tracking line showing the motion of a microrobot scanning; (f) Image by stitching the magnified area from individual video frames^[39]

Fig. 12. (a) The SEM image of the silicon nanostructure grating (SNG) with a period of 278 nm and a 139 nm line-width; (b) The SNG image by the trapped PS sphere; (c) The SNG image assisted by a trapped MF sphere^[41]

Fig. 13. (a) Optical upright microscope; (b) Z-axis translator; (c) A custom aluminum frame for clamping the glass microsphere array chip^[45]; (d) Fabricated microsphere array chip; (e) Schematic of the fabrication process of the microsphere array chip^[53]; (f) Super objective was made by integrating a conventional microscope objective lens using a adaptor ^[48]; (g) Preparation of PCM lens and installation ^[49]

Fig. 14. Super-resolution images scanning and stitching. (a)-(c) Microsphere array^[53]; (d)-(f) Unibody PCM objective ^[49]