Method And Experimental Research On Optical Super-Resolution Fast Imaging Based On Sphere-Crown Lens

With the development of science and technology,a variety of micro-imaging technology has broken through the optical diffraction limit of 200nm.Microsphere super-resolution imaging is one of them.This imaging technology is a method that the microsphere,which is placed on the surface of the sample,is used to obtain super-resolution image by the optical microscope.Microsphere super-resolution imaging has the advantages of real-time,efficient,easy operation,low cost,in-situ observation and so on.Therefore,it has broad prospects for development.However,the small field-of-view of microspheres limit its practical application.In order to enlarge the field-of-view,image mosaic software is used to stitch the images of continuous areas obtained by the microsphere,which reduces the efficiency and real-time of the microsphere imaging.As a result,microsphere super-resolution imaging can not be widely used.In this paper,"sphere-crown" lens,obtaining optical super-resolution images by fast scanning and stitching,is proposed to solve the problems of low efficiency and poor real-time in large area imaging of microspheres.Firstly,the theory and simulation are used to analyse that the"sphere-crown" structure not only enable the BTG microspheres to image in the air,but also attach the ability of super-resolution imaging to large diameter microspheres,so that a larger area of super-resolution image can be obtained at a time and the efficiency of stitching images is improved.Moreover,the automatic scanning and stitching imaging system can increase the scanning speed of microspheres.it can automatically capture and stitch images and then images are obtained in real time.Verified by experiment,this imaging method based on the "sphere-crown" lens can realize fast imaging through large-area stitching for both Blu ray disc and circuit structures in chips in the air,and it shows a broad application prospect.The main contents of this paper are as follows:(1)Based on the theoretical and simulation analysis of the factors affecting the super-resolution imaging of the microspheres,it is demonstrated that the upper part of the BTG microsphere in immersion medium has a higher imaging resolution in the air.The simulation results also show that the spherical crown structure has better imaging quality than others.Compared with the single microsphere,the spherical crown structure can locate the focus of nano jet to the bottom of the microsphere to achieve super-resolution imaging.A "sphere-crown" probe made by combining the microsphere with the spherical crown was used to scan the sample surface in the air and obtain the super-resolution image.(2)An automatic scanning platform based on the "sphere-crown" probe was designed and built.The kinematic analysis of the probe micromanipulator was carried out to verify that the motion of the micromanipulator meets the travel requirement of the probe.A set of automatic scanning and stitching imaging software is developed,by which,the "sphere-crown" probe can automatically scan the sample surface and collect super-resolution images.The images can be stitched in real time to enlarge the field-of-view.The automatic scanning platform and the automatic scanning and stitching imaging software are jointly tested.The software system is used to compensate the mechanical errors,so as to improve the quality of stitched images.(3)BTG microspheres with diameters of 150 μm,250 μm and 450 μm were made into"sphere-crown" lens respectively.Through imaging of the blu-ray disc,it was found that 150μm and 250 μm probes could obtain super-resolution images in the air.The limit resolution of the "sphere-crown" lens is not more than 90nm determined by the chip of electrode.The experiment results show that the quality of images obtained by the "sphere-crown" len immersed in water is higher than that in alcohol,and the magnification in water is higher.In terms of field-of view,"sphere-crown" lens greatly improves the super-resolution area and reduces the number of image acquisition.By using the automatic scanning and stitching imaging system,the wild-field of view images of blu-ray discs and circuit structures in chip are obtained in the air.For the observation of the inner wall of the groove,because of the small size of the "sphere-crown" lens,it can be moved to the inside of the groove to image the super-resolution structures on the side of the sample.The feasibility of the side-view super-resolution imaging.is verified by imaging of the blu-ray disc and the circuit structures in chip.