Research On Super-resolution Imaging By Dielectric Microsphere

Since it has the ability to realize non-fluorescence wide-field optical super-resolution imaging,the microsphere assisted microscopy attracts lots of attention.However,the imaging obtained by microsphere is low contrast ratio and its mechanism is not perfact distinct.Thus,it is necessary to further investigate the nature of super-resolution in microsphere imaging for its widespread applications.In this work,detailed investigation about the nature of microsphere imaging is presented.It contains optical properties of microsphere lens,the process of information collected by microsphere,the role of polarization contained in microsphere illumination and experiments about microsphere and microcylinder for super-resolution imaging.The research contains:(1)Analysis on the focus of microsphere lens and point imaging by microcylinder is implemented.(2)The quantitative model of transformation from evanescent waves to propagating waves is developed.The organized spatial frequency distribution contained in the process of information collected is studied and similary superoscillatory waveforms are found.The explanation about microsphere imaging is improved.(3)Investigation on the polarization of the focus of micro-cylinder and microsphere lens.And whispering gallery mode(WGM)illumination yielding out-of-phase components contained in the re-radiation of observed objects is described quantitatively.(4)Experiments about microsphere and microcylinder for super-resolution imaging improved by surrounded medium and illumination system are carried out.The micro-fiber lens is obtained using the method for tapered optical fibers fabrication and used for investigating the effect of different diameters for micro-fiber lens-based super-resolution imaging.The role of immersed liquid is investigated using simulations.In summary,we have explained WGM resonance improving the resolution of microsphere assisted microscopy,demonstrated WGM resonance can be enhanced by the transformation of evanescent waves to propagating waves,and detailed analyze the process of information collected by microsphere.Microsphere can affect the polarization of the incident waves.Based on this,we describe WGM illumination yielding out-of-phase components contained in the re-radiation of the observed objects.Immersing liquid assisting microsphere for optics ray selection can improve the resolution rate and the amount is related to the refractive index of microsphere and the medium itself.The results contribute to the knowledge of the microsphere-assisted microscopy mechanism and its potential applications.