XeCl准分子激光器寿命的研究

XeCI准分子激光器的寿命主要取决于HCI消耗的情况。实验结果表明,在环氧树脂筒的激光器室中,补充适量而价廉的HCI气体,器件寿命就可延长。我们在一次充入Xe气和Ar气的前提下,适时补充几次HCI,已获得大于1.03×10~6个脉冲输出,即在每秒5.3次的重复率和脉冲能量约100mJ的情况下,器件连续工作54hr还能正常运转。最大输出能量160mJ,文中还讨论了HCI对激光输出性能的影响。     

高功率二极管激光器寿命测试

 介绍了高功率激光二极管不同模式的失效机理，分析了激光二极管不同的寿命测试方法；在冷却水温20℃和实际工作温度下分别对封装的激光器进行了寿命测试。根据试验结果得出退化率，推算出准连续二极管激光器在水温20℃，电流90A，占空比为10%（500Hz，200μs）时，平均激光工作寿命为2.19×10⁹次脉冲；冷却水温35℃时，其平均激光工作寿命下降为1.65×10⁹次脉冲。由实验结果分析得出，高功率激光器封装工艺中的焊料沉积和多层焊接技术，以及工作环境温度是影响激光器可靠性和寿命的关键因素。     

基态HF分子和介质消耗对重复频率脉冲HF激光输出的影响

研究了氟化氢(HF)分子浓度以及工作介质消耗对激光脉冲能量的影响。受激光器内基态HF分子对激光的再吸收以及对激发态分子强弛豫的影响,激光脉冲能量随着激光器内HF分子浓度的升高而明显下降,HF分子浓度每增加1×10~(15) cm~(-3),激光脉冲能量约下降1.15%。1个激发态HF分子约产生0.8个光子,放电区内SF_6气体的分解率约为1%,单次放电过程中激光器内所消耗的工作介质较少,约为气体总量的1/(2×10~5)。实验结果表明:HF分子浓度对激光脉冲能量的影响较大,介质消耗对激光脉冲能量影响较小;通过在激光器内加入分子筛,可以将HF浓度控制在1.8×10~(15) cm~(-3)的水平。在两个因素的共同影响下,激光脉冲能量下降率约为10%。     

染料锁模激光器用于精密光学测量技术的研究

具有10~(-13)sec脉冲宽度的染料锁模激光器与具有同样时间分辨率的光学二次相关测量技术相结合,开辟了精密光学测量的新技术。     

非链式脉冲DF激光器放电生成物处理技术

非链式脉冲DF激光器放电产生的基态DF分子对激发态DF分子的消激发作用是影响激光器稳定工作的重要原因。为解决这一问题,分别采用3A和5A分子筛作为吸附剂进行实验研究。无分子筛时,激光器重频运转1 000个脉冲后,输出功率下降到初始功率的56%。分别使用3A、5A分子筛后,激光器重频运转脉冲个数达到5 000和6 800时,输出功率下降幅度仍然不超过20%,大大提高了激光器的稳定工作时间。实验结果表明,5A分子筛的吸附效率大于3A分子筛,且两种分子筛不仅对基态DF分子产生吸附,还对工作气体产生吸附,可通过及时补充工作气体提高激光器的稳定性。     

染料激光器输出特性的实验观测

一、前言自60年代染料激光器问世以来,由于它不仅具有激光器的一般特性,而且由于有机染料受激幅射产生的激光的波长已复盖了由紫外32lnm到红外1.3μm范围,同时染料激光器产生的超短脉冲的时间宽度已经可以压缩至15×10~(-15)s,其光带宽可以窄到δλ=6×10~(-5)nm。这些特性便使染料激光器在近年来得到迅速的发展。高单色性的可     

铥原子中等能量能级自然辐射寿命的时间分辨荧光测量

报道铥(Tm)原子10个中等能量激发能级自然辐射寿命的实验测量值.采用两台脉冲染料激光器将铥原子从基态激发到待测能级,再从铥原子激发态所释放的荧光随时间衰变的规律推算出自然辐射寿命值.测量精确度为10％.     

泵浦用高平均功率二极管激光器研制

针对高平均功率线阵二极管激光器(DL )芯片的工作要求,开展了相应的封装结构设计和高效冷却技术研究.封装的单条线阵DL连续输出激光功率50 W,工作寿命达到5 000 h,10%占空比准连续输出激光脉冲功率150 W,25%占空比准连续输出激光脉冲功率100 W,工作寿命达到5×109次脉冲.采用模块式封装方式由25个模块堆叠,制作出了连续激光功率1 kW和20%占空比工作脉冲功率2.5 kW的叠阵二极管激光器.     

消除激光接收中的荧光干扰

在固体激光器中,都是用闪光灯抽运法激励工作物质。一股,闪光灯的闪光时间在10~(-4)～10~(-3)数量级,在此期间,激光工作物质发出荧光,它在谐振腔来回反射,被激光工作物质放大,由前反射镜输出所需要的激光脉冲,激光脉冲的持续时间在10~(-8)数量级。激光测距机包括有发射光学系统和接收光学脉冲系统,一般这两个系统靠得很近,激光脉冲通过发     

短脉冲TEA CO_2激光多光子选择性离解高气压三氟甲烷体系

本文用一台自制的可调谐脉冲TEACO_2激光器及充气等离子开关所产生的脉宽约10～15ns、能量约0.2～0.4 J的短脉冲辐照高气压(200Torr)三氟甲烷样品,获得了较好的选择性离解及高的单步氘浓缩系数(β=7600_(-1500)~( 1000),与此对比,美国Marling等人的实验结果为:压力100 Torr时,β=11000_(-2000)~( 4000).     

Relaxation of green fluorescent protein chromophore anion observed by photodissociation in an electrostatic storage ring

The gas-phase absorption properties of the green fluorescent protein chromophore anion were studied using an electrostatic storage ring. The time sequence of neutral particles produced by photodissociation was detected following laser irradiation. The lifetimes of the photo-absorbed ions depended on their storage time in an ion trap before injection into the storage ring. The lifetime increased with the storage time and saturated, indicating a change in the population of rovibrationally excited states with respect to the storage time. Photodissociation neutral spectrum of the relaxed ions measured as a function of the laser wavelength was characterized by a narrow asymmetric shape, which was in good agreement with the photo fragment ion action spectrum reported recently.     

A practical CuBr laser with flowing buffer gas

Experiments on the lifetime of a CuBr laser with flowing neon as a buffer gas are reported. The CuBr laser with a discharge tube of inner diameter 18 mm, electrode separation 465 mm at an average output power of 3 W, an efficiency of 0.4% for a lifetime of 734 h is obtained. In consideration of the flow of the buffer gas and combined structure of the discharge tube we have achieved prolongation of the laser lifetime.     

Numerical solution of Boltzmann tranport equation for TEA CO2 laser having nitrogen-lean gas mixtures to predict laser characteristics and gas lifetime

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%.     

Long lifetime operation of an ArF-excimer laser

An experimental investigation to improve the lifetime of a discharge-excited ArF-excimer laser is presented. The three dominant factors restricting its lifetime are CF₄ generation in the laser gas, color-center formation in the optics and input power density reduction due to electrode ablation. Copper electrodes were superior to nickel electrodes in regard to electrode ablation. A gas lifetime of more than 10⁹ shots (about one month at 400 Hz) is shown for an ArF-excimer laser with a liquid-nitrogen trap and high-temperature zirconium alloy trap.     

Pressure Dependence of the Small-Signal Gain and Saturation Intensity of a Copper Bromide Laser

A pair of copper bromide lasers in an oscillator-amplifier configuration is used to investigate the small signal gain and saturation intensity as amplifying parameters and output power of lasers, versus pressure of buffer gas. It is shown that the amplifying parameters and laser output power have a maximum value at optimum buffer gas pressure of 11 Torr. The challenge between microscopic parameters such as stimulated emission cross section, laser upper level lifetime, and population inversion, which determine the values of laser characteristics respective to the operational pressure of buffer gas, are investigated. Thus an optimum delay time of about 10 ns is determined, and a maximum output power equivalent to about 12 W is extracted. The amplifying parameters and measured output power of laser versus delay times show some local maxima and minima at the delay time interval of 6-43 ns.     

Influence of spectral-dynamic effects in a laser and light guide on the dynamics of recirculation in a closed contour

The influence of stimulated emission delay, dynamic shift in generation frequency, residual charge effect, timing jitter of the radiation and excitation regime of an injection laser, as well as of dispersion in a fiber light guide on the data-internal storage time in an electrooptical contour is investigated. It is found that the storage duration of an interval depends strongly on the lifetime of nonequilibrium charge carriers, the simultaneous effect of a residual charge and jitter in an injection laser, as well as on the dc bias current of the laser. Belarusian State University, 4. F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 56–61, January–February, 1998.     

基于中红外量子级联激光器和石英增强光声光谱的CO超高灵敏度检测研究

采用石英增强光声光谱(QEPAS)技术对CO痕量气体展开检测研究. 为了实现超高灵敏度探测, 采用输出波长为4.6 μm的新颖中红外高功率分布反馈量子级联激光器为光源, 实现了对CO气体基频吸收带的激发与测量. 在优化了调制深度、气体压强和提高了CO分子的振动-转动弛豫速率后, 获得了1.95 ppbv的优异探测极限. 在分析检测结果的过程中, 讨论了能级寿命对信号强度的影响, 并对QEPAS信号强度的表达式进行了修正.     

Variation of the gas components of a TEA CO2 laser during its lifetime

An in situ mass-spectrometric sampling technique has been developed for lifetime studies of TEA CO₂ lasers. Using the new technique, an analysis of the gas components of a TEA CO₂ laser during its lifetime has been performed. The results show that the laser output pulse energy was strongly influenced by the oxygen concentration inside the device.     

Lifetime tests of rf-excited atomic xenon lasers

In this article we have, for the first time, performed a series of lifetime tests for the continuous wave radiofrequency-excited atomic xenon laser in the 1.7–3.9 μm regime. Different constructions and electrode materials are used to investigate the usefulness of this laser during long-term sealed-off operation. The influence of electrode material on wall–plasma interactions and the effect of gas impurities on the long-term operation of the laser are investigated and discussed. Received: 30 August 1999 / Published online: 23 February 2000     

Laser dye stability,part 12. The pyridinium salts

Improved laser output is demonstrated in KrF and XeCl lasers with x-ray preionization. The influence of gas composition, preionization geometry, x-ray dose,E/p value and temporal delay between x-ray pulse and laser discharge is discussed. In XeCl lasing has been achieved with an x-ray dose of 0.2 mR whereas approx. 3 mR are required for KrF. For both systems, the highest output energy and the lowest possibleE/p ratio were observed with Ne buffered gas mixtures. Dissociative attachment to halogen molecules on a ns time scale supported by a relatively slow laser voltage rise is recognized as the main electron loss channel preventing a long lifetime of the preionization electrons. High preionization intensity is thus desirable at the moment of voltage breakdown.