脉冲预电离纵向放电扩散冷却CO₂激光器研究

【作者】 于延宁；

【导师】 万重怡；

【作者基本信息】 中国科学院研究生院（电子学研究所） ， 物理电子学， 2002， 博士

【摘要】 近年来，纵向放电的脉冲气体激光器重新受到了人们的重视，一种小型的低功率的高重复频率脉冲激光器在激光探测、精细加工和光化学等许多应用领域，有重要的应用前景。本文研究了脉冲预电离的扩散冷却CO₂激光器的运转机理，提出采用脉冲预电离技术改善纵向脉冲放电的稳定性、降低工作电压和提高电光转换效率。提出了两种新的预电离技术。第一种技术称为“纵向多段脉冲预电离“技术。在玻璃放电管的外表面紧密套上若干圆环形电极，作为预电离电极。第二种技术是“横向螺旋脉冲预电离“技术。在玻璃放电管的外表面螺旋地粘上两条相对平行的金属箔，作为预电离电极。两种技术产生的效果基本相同。和无预电离的脉冲放电相比，激光器的工作电压下降了大约20％，电光转换效率提高了大约30％。 采用螺旋结构横向脉冲预电离技术首次研究了非自持纵向放电CO₂激光器，非自持激光器的主放电和输出功率由外加的预电离脉冲控制，激光器的可控性非常好。非自持放电使激光器的激发和电离过程分开，有利于使二者分别处于各自的最佳E／P值附近，放电的正阻抗特性使放电电路可以省去限流电阻，极大地提高激光器的实际效率。获得的最大的电光转换效率达19％。 本文还发展了一种采用Pspice软件对脉冲预电离放电进行瞬态模拟的理论分析方法，有利于激光器放电电路的优化设计。 最后，在前述理论和实验的基础上，提出了两种新型的脉冲预电离扩散冷却板条CO₂激光器方案，进行了可行性研究。这对进一步发展紧凑的高功率高重复频率激光器有重要意义。更多还原

【Abstract】 In recent years, the longitudinal pulsed-discharge gas lasers with diffusive cooling have received renewed interests. A compact low power pulsed laser with high repetition rate has potential importance in laser exploration, fine mechanical processing, photochemistry and so on. In this dissertation the operation mechanism of pulsed-preionization diffusive cooling CO₂, laser is studied. Pulsed preionization technology is put forward to improve the stability of discharge, decrease the operating voltage, and enhance the electro-optical efficiency. Two novel preionization technologies are presented. One is "multi-segmented coaxial pulsed-preionization ". A number of metal cirque electrodes surround equidistantly outside the glass discharge tube, acting as preionization electrodes. Another is "helical transverse-pulsed preionization ". Two comparatively parallel copper foil strips surround helically outside the glass discharge tube, acting as preionization electrodes. The two technologies produce similar results basically. In contrast to pulsed discharge without preionization, the working voltage of the laser falls about 20% and the electro-optical efficiency is improved approximately 30%.Non-selfsustained longitudinal discharge CO2 laser employing helical transverse-pulsed preionization technology is investigated for the first time. The main discharge and output power are well controlled by the pre-ionization pulser. In non-selfsustained discharge the excitation and ionization processes can be controlled separately, which is useful to optimize the E/P value of the discharge. The ballast resistance can be leaved out and the maximal electro-optical efficiency reaches 19%.This paper also presents a theoretical analyzing method for the instantaneous simulation of pulsed-preionization discharge by using Pspice software, it is favorableto the optimal design of the laser discharge circuit.Finally, based on the theoretical and experimental studies above, we bring forward two new schemes of pulsed-preionization slab CO: laser with diffusive cooling. This has important significance on further developing compact, high power, high repetition rate pulsed CO2 laser.更多还原