Super-resolution Imaging For Micro-nano Structure By Two-step Structured Illumination Modulation

Nowadays the level of micro nano manufacturing technology has become an important symbol to reflect the level of a country's science and technology.The micro nano devices are developing towards complex structures,whose characteristic size has extended from micrometer to nanometer scale,and the requirements for micro nano structure detection technology are higher and higher.As one of the basis of manufacturing technology,measurement needs to meet the increasingly complex needs of the structure of micro nano devices.However,the traditional optical detection method is limited by the diffraction limit.The lateral resolution is only about 1/2 wavelength.The visible light band is only 200 nm,which is difficult to meet the nanometer scale and even the molecular level microscopic observation and imaging.Therefore,how to further improve the resolution of the far field optical microscope has always been an important and urgent problem.The technology of structured illumination microscopy through the modulation of the frequency of the object,it can break through the diffraction limit and realize the superresolution imaging.The traditional structure illumination microscopy,by adding sine structured illumination on the object,the high frequency part beyond the diffraction limit in the diffraction limited system can be received by the system,then move the high frequency part back to the original position and add with the low frequent spectrum part using a specific algorithm,so as to restore a whole spectrum information.However,the traditional structured light super-resolution imaging method requires at least three images with different phase to achieve spectral separation.It not only requires high accuracy of phase shifting,but also affects the efficiency of image reconstruction seriously.Spectrum reconstruction is the key to the quality of super-resolution imaging,and spectrum separation is the key step of spectrum reconstruction.Whether the spectrum is effective and accurate separates directly affects whether the spectrum information can be restored completely and whether the final imaging quality is good.This paper proposes a super-resolution imaging for micro-nano structure by two-step structured illumination modulation,a new spectrum separation method without phase shift use the focal plane image without modulated and the image of object modulated by structured light obtain the high frequency information through specific superresolution imaging algorithm.Not only the algorithm is simple,but also reduces the system complexity and improve the efficiency of the reconstruction,especially in multiple illuminate directions to reconstruction of high frequency information in different directions,the reconstruction efficiency advantage is more obvious.In this paper,theoretical analysis,simulation and experimental analysis are described,and the method is verified.