Non-contact optical super-resolution imaging study based on height-variable microsphere

Super-resolution images can be achieved by coupling the microscale dielectric microsphere with white-light optical microscopy. This paper presented a method for adjusting the distance between microsphere and sample to study the imaging ability of the microsphere. By this method, the nanofeatures on the Blu-ray disc surface could be observed. The super-resolution images when microspheres at different heights were compared to analyse the changing trend of imaging ability with distance. The optical simulation results illustrated that super-resolution imaging ability was related to the position of the photonic nanojet. As the photonic nanojet was inside the sample, the super-resolution image could be achieved even if the microspheres didn't touch the sample. This work has great significance for manipulating microsphere to non-contact image.