Microscopy

Structured Illumination Microscopy (SIM) is one of the techniques which can surpass the Abbe diffraction limit. It is well suited for living cell imaging due to its high speed and low illumination energy features. For the reconstruction algorithm, a perfect structured illumination pattern is assumed. But in the real experiment, the illumination can be influenced by various effects because of the complexity of the experimental configuration, such as the polarization of the field, the diffraction from an aperture, the inclined illumination on the blazed grating. To analyse the influence of these effects on the final patter in focal plane, we perform a fast-physical optics modeling in the context of field tracing which is fully vectorial. The Local Plane Interface Approximation (LPIA) algorithm, a free space propagation algorithm and the Fourier Modal Method (FMM) are all combined in the calculation. We analyze the contrast and homogeneity of the illumination interference pattern at the sample plane, which should be accounted for in image processing. We find that the above mentioned various effects do influence the contrast and homogeneity of the pattern. We also suggest the parameters of the structured illumination system to obtain best contrast and homogeneity. Finally, the parameters of the optimized system can be obtained to apply to the experimental system.