【作者】 陈立；

【导师】 潘佰良；

【作者基本信息】 浙江大学 ， 光学， 2010， 博士

【摘要】 高重复率脉冲放电激励的锶蒸气激光是激光领域的研究热点之一,具有多种机制、丰富的谱线和较高的激光功率和效率等特点,能在430.5nm-6.45μm光谱范围输出多条瓦级以上功率的激光谱线,在微电子技术、材料处理、激光医疗和红外技术等领域具有广泛的应用前景。长期以来,人们对脉冲锶蒸气激光产生极大的兴趣和深入持续地研究并取得重要进展,但有关脉冲放电锶及其卤化锶蒸气激光中的微观动力学过程、激光机理和工作特性等还有待深入研究,结合国家自然科学基金项目的研究内容,论文较系统地开展了脉冲锶蒸气激光理论和实验研究工作,取得了一些创新成果,具有重要的学术和应用价值。论文第一章综述了金属蒸气激光尤其是锶蒸气激光的发展历史、研究背景和现状,分析讨论了不同机制中锶蒸气R-M跃迁激光、碰撞复合激光及其M-M跃迁激光的工作原理和技术路线,提出了锶蒸气激光中存在的问题、解决方法及课题的研究意义。第二章建立了一个反映高重复率脉冲放电激励的一价锶离子1090nm自终止激光和430.5nm复合激光交替振荡的动力学模型,得到了相关激光能级粒子数密度、电子密度和腔内光子数密度等微观参量的时间演化过程,分析解释了这两种激光交替振荡的发射过程、光电脉冲特性和粒子数反转机理,认为在放电早期和余辉期电子温度的急剧升高和降低是实现两种激光交替振荡的关键所在。第三章设计制作了小尺寸电泳式脉冲He-Sr+(Ca+)激光器,利用高重复率脉冲放电的电泳效应实现了金属锶或钙蒸气密度在放电区的均匀分布和稳定的激光输出,得到Sr+(Ca+)复合激光最大输出功率819(136)mW和56(5.9)mW/cm3功率密度的实验结果。分析讨论了脉冲频率、激励电压、氦压和430.5/373.3nm复合激光输出功率之间的关系,获得了一组较好的工作参量,为进一步研制该类激光的实用化器件奠定了基础。第四章设计制作了He-SrCl2蒸气激光器,成功地采用了锶的卤化物SrCl2代替金属锶为激光介质,实现了多条锶蒸气激光谱线的高效稳定输出,有效解决了纯金属锶激光工作时发生的锶蒸气和激光放电管之间剧烈的化学反应问题,提高了激光的运转寿命。获得了1.32W多谱线激光总功率和12.46mW／cm3功率密度,其中6.45μm波长占总功率78.1%,研究分析了He-SrCl2蒸气激光的光脉冲和电流脉冲的特性,发现-1μm／-3μm／6.45μm激光脉冲均出现在电流脉冲的下降沿并随着激光功率的增加有继续朝电流脉冲方向移动的趋势,并对此给予合理解释。第五章设计制作了可周期性更新缓冲气体后封离运转的金属蒸气激光系统,较系统地测量和分析了铜蒸气578/511nm激光的光谱线型随宏观工作参量的变化关系,发现激励电压、氖压和温度对578nm谱线结构影响较大。采用同样的方法研究了锶蒸气430.5nm复合激光的光谱结构,结果表明430.5nm谱线光谱结构稳定。更多还原

【Abstract】 The strontium vapor laser excited by HRR(high repetition rate) pulsed discharge is an important hotspot in the laser area, which has many characteristics including multiple laser lines(covering waveband from blue to infrared),with different mechanisms, higher output power and efficiency and so on. These lasers can be widely used in material processing, microelectronic technology, laser medical treatment and infrared technology. Scientists constantly have great interest in working on the output performance and the mechanism of strontium vapor laser, and make a lot of impornant results, however, the micro-kineitc process, the laser mechanism and the characteristics of strontium and strontium halide vapor lasers are still to be deeply investigated. In the paper the pulsed strontium laser is systematically studied whatever on theory or experiment aiming at accomplishing the task of National Natural Science Foundation Program, and some important results are achieved during the research.In Chapter 1, the development history, the background and the research state of metal vapour lasers(MVLs) especially the strontium and strontium halide vapor lasers are compendiously introduced. The principle and the technology of strontium vapor laser with different transtion mechanisms including the self-terminating laser, the collisional recombination laser and the metastable-metastable laser are discussed and analyzed. Some suggestions to solve the subsistent problems of strontium vapor laser and the research purpose are given out. In Chapter 2, a self-consistent model is developed to simulate the kinetics of alternate oscillation of self-terminating and recombination lasers(1090/430.5nm) in univalent ions of strontium excited by HRR pulsed discharge. Temporal behaviors of level population densities,the electron density and the cavity photon density are obtained. The emission process of alternate oscillation of the two lasers above, the characteristic of the laser pulse and the population inversion mechanism are also analyzed and explained. It is considered whether the electron temperature can rise up quickly in the early discharge and fall down rapidly during the discharge afterglow is the key to realize the alternate oscillation of self-terminating and recombination lasers in univalent ions of stroantium in experiment. In Chapter 3, a small-scale cataphoresis He-Sr+(Ca+) recombination lasers are made. By means of the cataphoresis effect in HRR pulsed discharge, the axial uniform distribution of metal vapor density and the stable laser output are realized. The maximum laser output power of 819(136)mW and the specific power of 56(5.9)mW/cm3 are obtained for Sr+(Ca+) recombination lasers, respectively. Dependences of working parameters such as the pulsed frequency, the supply voltage and the helium pressure on laser output characteristics are measured and discussed. and a set of optimal work parameters is got. It provides a new way to make a practical device of this kind of laser. In Chaper 4, an investigation of a He-SrCl2 vapor laser excited by Blumlein discharge circuit is made. SrCl2 compound is successfully employed as a lasant in exploring the discharge excitation strontium vapour laser with a novel laser discharge tube, and the laser output at multiple lines(-1μm,-3μm and 6.45μm) in strontium vapor are realized. The problem of the intense chemical reaction between strontium vapor and discharge tube in the metallic strontium laser is effectively solved, which prolongs the lifetime of the laser. Total output power of multiline of 1.32W and the power specific of 12.46mW/cm3 are achieved, in which the component of the 6.45μm laser line accounts for 78.1%.The characteristics of laser and current pulses in a He-SrCl2 vapor laser are measured and analyzed,and the improtant experimental rules are got In Chapter 5, a sealed operation MVL with periodical refreshment of the buffer gas are designed and made. The spectral structures of 578nm and 511nm laser lines, produced by CuBr laser with lower Ne buffer gas pressure are measured and analyzed under different working temperature and exciting voltage. It is found that 578nm laser line is closely dependent on the work temperature and the exciting voltage, but 511nm laser lines not. In the same way the study on the spectral structure of 430.5nm strontium ion recombination laser is done, and it is shown that the line shape of 430.5nm laser is stable and monochromatic.更多还原