Fig. 1. (a) CHQ microlens-assisted super-resolution microscopy^[19]; (b) SiO₂ microsphere-assisted super-resolution microscopy^[20]; (c) Scanning microsphere super-resolution microscopy^[26]; (d) Self-assembled TiO₂ particles for super-resolution microscopy^[30]; (e) Liquid droplet-assisted super-resolution microscopy^[31]; (f) Surface plasmon resonance-enhanced super-resolution microscopy^[39]

Fig. 2. (a) A photonic nanojet and (b) a photonic hook; (c) Super-resolution imaging technology based on photonic hooks^[47]

Fig. 3. (a) Schematic drawing of the microsphere imaging system used by Duan et al.; (b) The corresponding imaging simulation results^[45]

Fig. 4. (a) Schematic drawing of the microsphere imaging system; (b) 2D simulation model based on microsphere imaging system; (c) The images of off-axis single point sources formed by microspheres; (d) The images formed by the microspheres for the two point sources distributed symmetrically along the optical axis; (e) The influence of the mode of the point sources (out of phase, in phase, incoherent) on the resolution of the microsphere imaging system^[61]

Fig. 5. (a)-(d) The images of the two neighboring point sources formed by microspheres when the microspheres are on Mie resonance; (e)-(h) The images of the two neighboring point sources formed by the microspheres when the microspheres are not on Mie resonance^[62]

Fig. 6. (a) The photonic nanojet of a microlens can be obtained by simulating its focusing performance for plane waves; (b) The point spread function of a microlens can be obtained by simulating its imaging properties for point sources^[63]

Fig. 7. (a) The steps for the three-dimensional imaging simulation: (i) The near-field full-wave simulation, the near-to-far-field transformation, the far-field imaging simulation and (ii) the simulation for the formation of virtual images; (b) The simulated microsphere’s imaging performance for the two point sources with various gaps between them; (c) The simulation of microsphere’s imaging for metallic grating structures and (d) the corresponding simulation results show that the metallic lines with 75 nm separation can be resolved by the microsphere; (e) Microsphere imaging system has a higher resolution for metallic samples: (i), (iii) Metallic microstructures; (ii), (iv) Non-metallic microstructures with the same dimension^[64]