Can Be Used For Transient Wave Surface Real-time Detection Theory And Research

The research of Inertial Confinement Fusion (ICF) techniques is a powerful act to resolve the energy crisis and environment pollution. To make the laser beam have a good spatial distribution, it involves techniques in many fields, such as optics, mechanics and electronics etc. Furthermore, measurement of wavefront aberration plays a great important role in high power laser system. The thesis is directed by the Uinin Foundation and National Natural Science Foundation program-"Laser Wavefront aberration measurement with radial shearing method". This program is to be fulfilled by several sequential steps and what will be described in this thesis belongs to the first step, which includes construction of the radial shearing interferometer, algorithm and method suitable to demodulate single interferogram and analysis on test result. Main research work and new ideas as followed:The importance of qualifying the wavefront distortion in ICF system is recounted and a simple, compact radial shering interferometer based on spatial phase modulation is proposed.The principle and typical structure of the radial shearing interferometer is described and a rapid, precise iterative method is proposed and fulfilled.The theory of spatial phase modulation and the Fourier transform method is described considerably and some important issue, such as frequency leak effect, discontinuity, selection of carrier frequency and so on is analysed.The process of radial shearing iterative reconstruction, Fourier fringe analysis with a typical wavefront is simulated and it approved a precision above A l\ 00 can be achieved, which can meet the need of the ICF system.A method based on grads is proposed to recognize the radius and center of the fringe aperture only by single interferogram.With Matcom, Visual C++ and OpenGL, a effective software of the system is fulfilled.In the thesis, some new idea is proposed, such as the effective iterative method, 2D Fourier Transform method which is helpful to simplify the system andcontrol the noise effectively, the description of the relative between aforementioned two method and so on.