Research On The Far Field Optical Super Resolution Imaing

Optical microscope is one of the most important scientific achievements in the history of mankind. However, due to the presence of diffraction limit, the transverse resolution is limited to about half of the illuminating wavelength. Meanwhile, microscope with a resolution better than the diffraction limit would have a profound effect on a number of interdisciplinary areas from the imaging of cells to the inspection of semiconductor devices. Therefore, how to break the optical diffraction limit to achieve the super resolution imaing will have a very important scientific significance. In this dissertation, we focus on the far-field super resolution imaging technology and the main research works are listed below:1. In the area of super-resolution imaging based on the dielectric microsphere, the mechanism of the enhanced resolution was studied based on the Fourier optics. The interaction of the evanescent wave scattered from the sample with the microsphere was investigated detailedly. The dependence of the imaging resolution and magnification on the geometrical parameters of the microsphere was also analyzed. Experiments were also taken to verify the theoretical analysis and the influence of the immersed liquid to the imaging properties was analyzed by the finite-difference time-domain simulation and spectrum analysis method. Finally, a novel thin film was proposed and fabricated for optical super-resolution imaging.2. In the field of plasmonic lens with nanoslits of variant widths, the design method was firstly presented and then the influences of the parameters on the properties of focusing were investigated. Then a new method for the design of multi-focus plasmonic lens based on holography was proposed. The desired output light field distribution and the incident plane wave are treated as object wave and reference wave, respectively. Then the amplitude distribution of interference light field is discarded and only the phase distribution is recorded. Finally the width of each nanoslit is determined according to this phase information. Numerical simulation of multi-focus lens design was also performed through finite-difference time-domain method and the result confirmed the feasibility of our method.3. In the field of structured illumination microscopy, a new techmology based on the nano-pillar array and nano-sphere array was proposed. And the mechanism of super resolution imaging with this technology was ananlyzed. Finally, numerical simulation was performed to verify its feasibility. And the result showed that the resolution of 100 nm could be achieved, which is a sixth of the incident wavelength.