DMD-based Multi-mode Super Resolution Fluorescence Microscopy

Compared with traditional optical microscopy,fluorescence microscopy bears higher Signal to Noise Ratio and specificity,which earns it great popularity.However,the resolution of fluorescence microscopy is limited by diffraction effect,which is the same as int the case of optical microscopy.Several super resolution fluorescence microscopy techniques have been developed to solve this problem,among which Structured Illumination Microscopy(SIM)features low photo-toxicity with comparative high imaging speed.As a result,SIM is rather attractive in the field of cytobiology research.Sinusoidal illumination is applied in SIM and its frequency shifting effect results in resolution improvement.Digital Micromirrors Device(DMD)has been utilized in SIM,but speckle effect arises if laser source is used,which decreases imaging quality.Consequently non-coherent sources are employed in DMD-based SIM imaging system.A novel despeckle method based on scanning MEMS mirror is proposed,which can resolve the speckle issue.With this method,a laser illuminated and DMD based fluorescence microscopy system is constructed.SIM imaging with sinusoidal illumination is achieved by this system.With DMD being digitally programmable,blind-SIM imaging is improved in terms of experimental images quantity,which is reduced to dozens from several hundreds or thousands.So the efficiency of blind-SIM is greatly increased.Also,super resolution optical fluctuation imaging(SOFI)is meliorated on this system through introducing temporal fluorescence undulation via DMD illumination modulating.The number of experimental images needed for SOFI imaging is decreased by one order and the dependence on special fluorescent dyes is abated.What's more,a super resolution reconstruction algorithm for SIM imaging is developed in the framework of least squares regression,which applies for SIM data both under sinusoidal and non-sinusoidal structured illumination.This algorithm is non-iterative and conducted mainly in spatial field,which raises the efficiency of super resolution reconstruction of SIM imaging.