Research On Ultrafast Two-dimensional Imaging Technology Based On Streak Camera

The realization of high temporal and space resolution diagnosis of various ultrafast phenomena in the process of Inertial Confinement Fusion(ICF)is very important for the success of ICF.The measurement of visible light is meaningful,which can get some crucial physical parameters directly.However,the current imaging diagnosis technologies are far from meeting the diagnosis requirements.The imaging fiber bundles system is formed by two-dimensional to one-dimensional imaging fiber bundles coupling streak camera.Since both imaging fiber bundles system and compressed ultrafast photography system(CUP system)are recorded by a streak camera,they both have the diagnostic advantages of the streak camera,which means the fastest temporal resolution in the world(usually on the magnitude of ps),showing these two ultrafast imaging technologies based on streak camera have broad application prospects in ICF.However,due to the complex physical process of ICF,the above two ultrafast two-dimensional imaging technologies cannot be directly applied to the diagnosis of ICF,therefore,the further research on its application is needed.Based on the above,we firstly introduced these two ultrafast two-dimensional imaging technologies in detail,and proposed that these two technologies should be applied to different ultrafast physical diagnosis according to their characteristics.The CUP system is applied to the shockwave diagnosis,forming a new two-dimensional shockwave diagnosis system with ultrafast temporal resolution.The imaging fiber bundles system is applied to the near backscatter light diagnosis,forming a new two-dimensional near backscatter light diagnosis system with ultrafast temporal resolution.Based on the experimental diagnosis,by establishing a simplified and several more realistic shockwave models,we theoretically verified the possibility of applying the CUP system to the shockwave diagnosis,further illustrating the feasibility of the new two-dimensional shockwave diagnosis system with ultrafast temporal resolution.By establishing an offline CUP system in the laboratory,we successfully restored a process with a temporal resolution of 2ps where a spot changed over time.On the basis,the new two-dimensional shockwave diagnosis system with ultrafast temporal resolution was built in Shenguang-III facility and participated in the shockwave diagnosis.And according to the experiment results the actual situation,this system was optimized and improved: the external CCD has been eliminated,which provided great convenience for the experimental process;the use of two 4f systems instead of beam splitting cube has greatly improved the light intensity and the image contrast;we found an algorithm that was more suitable for reconstructing the fringe image of shock wave.All the above laid a firm foundation for the further application.At the same time,the two-dimensional to one-dimensional imaging fiber bundles was studied through an offline experiment.The results prove that the system has the ability of two-dimensional images measurement.On the basis,the new two-dimensional near backscatter light diagnosis system with ultrafast temporal resolution was built in Shenguang-III facility and participated in the near backscatter light diagnosis.It achieved the two-dimensional measurement with a temporal resolution up to 5ps.At last,according to the actual situation,this system was optimized and improved:the arrangement of optical fibers in the two-dimensional end of imaging fiber bundles has been improved and the optical fibers with smaller diameter were used to make this system have a higher spatial resolution to complete the measurement of higher precision physical process under extreme conditions.The study of this paper will help in achieving the ultrafast two-dimensional diagnosis of the visible light in ICF and providing a reference for other nuclear fusion diagnosis,which is of great significance for the successful achievement of ICF.