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横向激励大气压(transversely excited atmospheric,TEA)CO2激光器的放电稳定性是决定该类型激光器应用效果的关键因素。通过对采用电感充放电电路的紫外预电离激光器的实验研究,得到了激光器放电动态过程的规律,并发现残余振荡是主放电后发生弧光放电的主要原因。实验中采用不同配比的气体,并对电感充放电电路与改进后的硅堆充放电电路进行了比较。实验结果表明:增加充电电感值可以降低主放电结束后储能电容上的残余电压;而采用硅堆放电电路在主放电后仅有相对幅值很低的稳定残压,两种方案都大幅度抑制了弧光放电的形成,有效地提高了激光单脉冲能量。 相似文献
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从均匀场电极理论出发,计算并讨论了近似Rogowski电极、Chang电极(含紧凑式Chang电极)和Ernst电极的形状、理论电场分布和实际电场分布。对实验室所用的几种电极进行了脉冲放电实验,从而获得了TEA CO2激光器的放电参数与输出特性,并对这些结果进行了比较和分析。计算表明,在基本参数相同的情况下,Ernst电极具有最紧凑的外形和最佳的均匀电场分布。实验表明,采用近似Rogowski电极的TEA CO2激光器具有最大放电辉光范围和44 kV的最小放电击穿电压;采用Ernst电极的TEA CO2激光器具有25 J的最高单脉冲能量和最大17.2%的斜率效率。最后提出了TEA CO2激光器主电极的选择建议。 相似文献
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利用像增强CCD相机对脉冲CO2激光器的放电区进行观测,获得了放电辉光的发展过程,由此研究了长脉冲放电电路和短脉冲放电电路对放电过程的影响。发现普通电容放电电路(长脉冲放电电路)存在与自持放电阶段相对应的二次辉光;采用磁压缩开关的短脉冲放电电路,预电离出现较晚,但预电离辉光峰值和主放电辉光峰值之间间距较短,不存在自持放电阶段,只观测到一次强辉光。长脉冲放电电路与短脉冲放电电路在放电的后期均存在一个阴极位降区形成的过程。短脉冲放电电路有利于产生更窄的脉宽和更高的峰值功率。 相似文献
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用电子束蒸发方法制备了HfO2薄膜,根据镀膜前后基片曲率半径的变化,用Stoney公式计算了薄膜应力,讨论了沉积温度对薄膜残余应力的影响。结果发现,HfO2薄膜的残余应力均为张应力,应力值随沉积温度的升高先增大后减小,在280 ℃左右出现极大值。对样品进行了XRD测试,从微观结构上对实验结果进行了分析,发现微结构演变引起的内应力变化是引起薄膜残余应力改变的主要因素,HfO2薄膜在所选沉积温度60~350 ℃内出现了晶态转变,堆积密度随温度升高而增大。 相似文献
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电感在现代电子电路中应用广泛,大量的存在于滤波、耦合、振荡等电路中,因此如果可以准确的测量电感的阻值具有重大的意义[1-2]。现今,电感的测量大部分是测用电桥法,高精度的电桥测试仪器是比较昂贵的。通过对电感的特点,以及现有的测量方式进行了研究,设计了一种高精度、低成本的电感测试仪。该仪器采用具有不同电流值的恒流源反复对电感进行正反向充电,然后根据检测的不同电流值下的放电时间求取电感值取其平均值,最后得出待测的电感值。本文完成了恒流源充放电电路、电源电路、开关充放电电路、检测电路以及控制电路的设计[3-4]。该装置的电感测量误差在±5%以内,具有灵敏度高,相应速度快、成本低等特点,具有广泛的应用意义。 相似文献
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注入锁定TEA CO2激光器激光脉冲特性分析 总被引:1,自引:0,他引:1
本文在一般的TEACO2激光器的动力学方程的基础上,给出注入锁定情况下TEACO2激光器的动力学方程组,并进行数值计算,结果表明,TEACO2激光器注入锁定激光脉冲宽度比自由运转时的变宽了,脉冲峰值功率降低,而且激光脉冲产生的时间提前,这与实验规律相吻合。 相似文献
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一些低增益弱线CO2激光光谱在分离某种同位素方面是非常有用的。在成比例的混合气体中很难获得这些谱线的输出,须适当提高CO2和N2的含量,但结果给主电极的辉光放电带来了困难。通过对改装后的双预电离放电回路的参量进行调节,实现了对预电离的单独控制,有利于增强预电离效果,使高含量的CO2混合气体的放电和出光成为可能。理论和实验证明了双预电离能较好地改善TEA CO2激光器的放电性能,尤其是有望实现用于分离某些同位素的弱线输出。 相似文献
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Fanjiang Meng Dianjun Li Shouhong Sun Fei Chen Heqi Wang Guilong Yang Chunrui Wang Jin Guo Lihong Guo Xinhong Ge Chunlei Shao Shiming Li 《Journal of Russian Laser Research》2012,33(4):362-368
High-power repetitively-pulsed TEA CO2 lasers are excited by a glow discharge, and it turns out to be the arc discharge under some conditions. The arc-discharge is a disadvantageous condition and must be avoided. According to the Faraday electromagnetism induction principle, the arc-discharge monitoring system with a magnetic-field probe is designed for high-power repetitively-pulsed TEA CO2 lasers. The magnetic-field variation induced by the discharge current can be tested, and the discharge state can be distinguished according to the output induction voltage. Experimental results show that the magnetic-field induction voltages generated by a glow discharge and an arc discharge are very different ones. The maximum induction voltage of the glow discharge is 2.0?V, while the minimum induction voltage of the arc discharge is 2.5?C4?V. Three alarm levels are set by measuring the arc-discharge intensities. At the first level, automatic filling?Cexhausting equipment starts to refresh the gas media, at the second level, the laser repetition rate is reduced, and at the third level the laser operation stops immediately. As a result, the working reliability of a high-power repetitively-pulsed TEA CO2 laser system can be improved significantly by using the arc-discharge monitoring system. 相似文献
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A simple and sensitive technique, which utilizes the sensing of both the discharge current and the visible light emission from the discharge, has been developed to detect the arc formation during the operation of a high repetition rate TEA CO2 laser. It is shown that the optical detection in the visible spectral region is more sensitive than that it is in the UV region and hence can be used more effectively to monitor the onset of arc formation, while the current signal is useful in the strong arc formation regime. We demonstrate that the trigger signals generated by both the methods can be employed for reliable protection of the laser system from catastrophic damage due to deleterious arc formation. 相似文献
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Selective laser isotope separation by TEA CO2 laser often needs short tail-free pulses. Using laser mixtures having very little nitrogen almost tail free laser pulses can be generated. The laser pulse characteristics and its gas lifetime is an important issue for long-term laser operation. Boltzmann transport equation is therefore solved numerically for TEA CO2 laser gas mixtures having very little nitrogen to predict electron energy distribution function (EEDF). The distribution function is used to calculate various excitation and dissociation rate of CO2 to predict laser pulse characteristics and laser gas lifetime, respectively.Laser rate equations have been solved with the calculated excitation rates for numerically evaluated discharge current and voltage profiles to calculate laser pulse shape. The calculated laser pulse shape and duration are in good agreement with the measured laser characteristics. The gas lifetime is estimated by integrating the equation governing the dissociation of CO2. An experimental study of gas lifetime was carried out using quadrapole mass analyzer for such mixtures to estimate the O2 being produced due to dissociation of CO2 in the pulse discharge. The theoretically calculated O2 concentration in the laser gas mixture matches with experimentally observed value. In the present TEA CO2 laser system, for stable discharge the O2 concentration should be below 0.2%. 相似文献
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J.F. Figueira 《Optics Communications》1974,11(3):220-224
Small signal gain measurements of a uv preionized TEA CO2 laser system are described. It is shown that the relative timing of preionization with respect to the main discharge determines the amount of electrical energy that can be deposited in the gas prior to arc formation. 相似文献
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研究了电激励脉冲HF激光工作介质SF6/C2H6混合气体的放电特性。通过对放电等离子体荧光图像和放电波形的测量,分析比较了不同条件下放电稳定性、剩余电压、能量沉积效率等特性参数的变化情况。实验结果表明:混合气体的放电过程存在主放电、剩余电压维持和电弧放电3个阶段,各阶段的放电特性有所差异;提高充电电压有利于放电能量的有效沉积,也会使不稳定的电弧放电提前;增加C2H6原子分数能起到抑制电弧放电的作用;混合气体总压的增加会导致剩余电压的提高以及辉光放电的能量沉积效率的降低;最佳的能量沉积出现在电弧放电阶段与辉光放电阶段即将融合的临界状态。 相似文献
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从激光推进的要求出发,阐述了用于激光推进的高功率激光器的选择原则,即激光器必须满足:(1)高的平均功率和峰值功率;(2)高的单脉冲能量;(3)高的重复频率;(4)优良的大气传输特性。主要分析了目前YAG固体激光器、自由电子激光器和TEA脉冲CO2激光器的特点,通过上述4个方面性能的比较,认为在目前水平下,TEA脉冲CO2激光器是进行激光推进的首选强激光源,其优点表现在:功率可达10kW量级,单脉冲能量可达0.5~1kJ,重复频率为20~40Hz;激光波长处于大气传输窗口,对大气变化不敏感;工作物质快速流动,不存在热透镜效应和破坏阈值;相关光学元件易于制造;光束质量较好;运行成本低。 相似文献