Experiment Survey Of Laser Beam Quality Parameters Of The Unstable Resonator And Its Theoretic Analyzing

Since the laser technology invented, the continual wave laser and the pulse laserhave simultaneously like twin brothers flourished .The giant pulse laser worth is toapply to the process of drilling a hole or laser bombardment against a material and thisapplication is unable to substituted. How to enhance the energy of each pulse? How toenhance the peak power of each pulse? This is a question that the giant pulse laserrenewed unceasingly and progressing unceasingly wants to reply. MOPA is a method tosolve the issue under the limit of stable resonator, but the invention of unstableresonator is a breakthrough and an innovation to traditional laser theory, It effectivelyenhanced the energy and the peak power per pulse. Since A. E. Siegman published hisfirst article about unstable resonator in 1965, many scientists and engineers havecomprehensively researched into it's mechanics and developed it's type. There also aresome of domestic research reports, but absence of a more systematic experiment studyfor two kind of typical unstable resonator, hard-edge output mirror resonator and Gaussoutput mirror resonator through the comparison. This article firstly andcomprehensively outlined the unstable resonator principle of design, the unique feature,the output way and the practical type. Then separately described two measurementexperiments: the first, the laser beam quality parameters of the Positive-branch unstableresonator with the hard-edge output mirror have been surveyed by the help of theaverage instruments and, the second, that of the near-concentric unstable resonator withthe Gaussian output mirror also have been survey by the help of the professionalinstruments. The two kinds of unstable cavity are made by our self.In preceding kind of situation, a reflections mirror of the curvature radius of 5meters, a CCD head and a general software grasping photo is used into experiments.From these ordinary tools, the pulse beam waist pictures of a pulse of width 20ns areattained at the mirror focal-plane. In the latter kind of situation, the all-automatic M2analyzer and the optic-spot analyzer are utilized. We surveyed the optic-spots and thebeam quality, M2 for the near-concentric unstable resonator with symmetry Gaussmirror. Finally, this article has analyzed the measurement result. These results have theimportant reference significance to the unstable cavity design.