Design and analysis of high speed high resolution cross structured illumination confocal microscopy

Abstract

Recently, the demand for high speed high resolution optical measurement system is growing in numerous fields, for example, semi-conductor/FPD industries, bio-medical and surface/material sciences, etc. In order to meet the demand of these fields, many studies have been carried out. In order to overcome the resolution limit, many researchers have demonstrated new methods such as confocal, two-photon, stimulated emission depletion, 4Pi confocal, structured illumination microscopy, etc. The resolution of conventional microscopy has been improved over the diffraction limits in structured illumination microscopy (SIM). By using laterally SI in widefield, non-confocal microscope, it is possible to achieve lateral resolution well beyond the classical limit without discarding any emission light. However, a total of nine images are necessary. In order to double the axial as well as the lateral resolution with true optical sectioning, a total of fifteen images should be acquired. This leads the speed of the acquisition image to be slow and the process of the image reconstruction to be complex. Several researches have been carried out for increasing the image acquisition speed of SIM. However, actual real-time imaging of SIM is not performed yet. In this thesis, the high speed high resolution cross structured illumination confocal microscope (CSICM) is proposed. The proposed CSICM obtain two times enhanced lateral resolution, optical sectioning ability and fast image acquisition speed. CSICM combines the cross SIM and the line beam scanning confocal microscope. The cross SI pattern is generated by using the 2-D diffractive grating. Performances of the conventional SI and the cross SI are quantitatively compared by the analysis of the modulation transfer function. As a result, the cross SI method shows similar resolution to conventional SI method except along 45 degree and 135 degree directions. Since the cross SI method has no rotation of the grating or the specimen, fast...