Fast-axial-flow CO2 slab laser with a narrow-gap RFdischarge operating at high pressure

A fast-axial-flow carbon dioxide laser is operated with a rectangular cross section, radio frequency excited, slab discharge. The narrow electrode gap and the series capacitance of the discharge tube walls produce excellent discharge stability at higher input power density and pressure than in conventional fast-axial-flow lasers. For a single-section test discharge, the mass flow per unit cross-sectional area is improved by high-pressure operation and the mass flow choking effect at sonic gas exit velocity is avoided. For CW operation, the discharge power density has been increased to 200 W·cm^-3 and laser operation demonstrated at a pressure of 500 torr. In pulsed operation at pressures of 300-400 torr, repetition frequencies of 15 kHz have been achieved with the pulse duration reduced to 15-25 μs, suitable for materials processing of low thermal conductivity materials     

多功能CO2激光器及其应用

研制成功多功能CO2激光器。该激光器输出TEM00高斯基模,输出波长在9.2-10.8μm范围内能够调谐,可以输出9P、9R和10P、10R支跃迁谱带的谱线共计30余条;能够以连续放电方式运转输出连续激光,输出功率5W左右（腔内不加声光调制器时输出25W）,也可以运转在脉冲放电方式输出＂长＂脉冲激光,还可以在连续放电运转条件下经过腔内Q突变方式输出＂短＂脉冲激光;在以脉冲方式工作时,可以选择单脉冲方式输出,也可以选择最高频率为10kHz的重复脉冲,激光脉宽（FWHM）可以在百纳秒至几十毫秒量级范围内变化,最高峰值功率超过数千瓦。该激光器在科研、教学以及激光医学等很多领域都具有实际应用价值。     

MOPA方式高峰值功率脉冲光纤放大器模拟

为了研究如何从脉冲种子光经放大器后获得能量为毫焦级、纳秒级脉宽的激光脉冲,以及重频、受激喇曼效应对输出激光脉冲的影响,采用基于主振荡动率放大方式建立了3级脉冲双包层掺Yb光纤放大器的瞬态理论模型。在不同重频下对能量为10nJ、脉宽为100ns的脉冲种子光经放大后的脉冲能量、峰值功率、平均功率、脉宽及受激喇曼效应进行了数值模拟。计算数据表明,当重频小于200Hz时输出激光脉冲的能量、波形受重频的影响很小,可以忽略不计,在适当参量下受激喇曼效应对各级放大输出几乎没有影响。结果表明,适当选择3级光纤放大器的各项参量可以实现毫焦级的激光脉冲输出。     

The interruption of vacuum arcs at high DC voltages

In 1967, it was observed by the authors that an axial magnetic field applied to a vacuum-arc discharge in a coaxial diode was capable of extinguishing the discharge. A continuing effort to develop a high-voltage dc arc interrupter has resulted in a simple, lightweight device capable of interrupting 800 A at 25 kV. Operation at higher levels was limited, not by the interrupter, but by the lack of availability of adequate power supplies. This device has been operated at repetition frequencies of several pulses per second. Successful operation at a frequency of 1 kHz has been achieved at lower power levels. The turn-on and turn-off times are, respectively, as short as one and two microseconds, The pulsewidth is continuously variable from a few microseconds to infinity (dc operation). It has been demonstrated that operation above 10 kV requires very pure materials and the use of ultra-high vacuum techniques. Among the many uses for the interrupter are those in high-power modulators and high-power inverters. An enticing future application is for switching in high-voltage dc power transmission systems.     

放电激励重复频率HF激光器稳定输出实验研究

在放电激励重复频率气体激光研究中,激光器重复频率运行能量稳定输出是提高其输出平均功率及其实用化的基础。利用实验室已建立的单脉冲输出能量焦耳级的放电激励重复频率脉冲HF激光装置,通过调节气体介质循环速率及优化实验条件,开展激光器重复频率运行稳定输出实验研究,获得激光器重复频率运行时能量稳定输出的最佳工作条件。研究结果表明,随着运行频率的上升,激光输出能量衰减较快;增大气体介质循环速率有利于改善放电稳定性,提高激光器重复频率运行时输出能量稳定性。当混合气体工作介质以3.5m/s的流速循环时,激光器可实现1～50Hz重复频率激光输出,在重复频率50Hz运行时稳定输出能量约130mJ,能量波动约5%。     

A high repetition rate ion laser spanning the 195-225 nm spectral region

This paper describes the construction and operation of a water-cooled noble gas ion laser which generates average powers of the order of a milliwatt at 5 strong transitions between 195 and 225 nm. This pulsed laser has been operated at repetition rates up to 200 Hz and has produced average powers up to 5.1 mW at 219.2 nm. The pressure and voltage dependence of output power, along with preionization effects, gain, saturation intensities, and the effects of discharge current pulse length are discussed. The optical pulses can be precisely synchronized with respect to an electrical reference signal, and the laser operates at all wavelengths with Brewster windows, permitting convenient interchanging of resonator mirrors. This device has been designed for use as an ultraviolet illuminator in a photoelectron microscope.     

1-ns high-power high-repetitive excimer laser oscillator

A 1-ns high-power high-repetitive excimer laser oscillator has been developed for which the peak power obtained was more than 1 MW with 1-ns pulse width for both XeCl and KrF gas mixtures. The characteristic output power per unit active volume is calculated to be more than 2 GW/L, which is nearly one order larger than that extracted from usual discharge devices. It is inferred that the gain depletion in the active medium under such an extremely large output power condition has led to successful pulse shortening. The device can be operated at a repetition frequency of at least 500 Hz without a gas circulation system. The beam divergence was reduced to near the diffraction limit, although the oscillated-pulse width is only 1 ns     

Mn/MnCl_2蒸气激光器

研制了以氯化锰为工作物质、氖作缓冲气体的连续脉冲锰蒸气激光器。观察到7根绿色激光谱线,激光输出的90％以上集中在5341谱线上。在重复率18.2千周时最大平均功率444毫瓦,效率0.05％。还观察到12900的红外激光输出。     

A pulse repetition frequency scaling law for the high repetition rate neutral barium laser

The variations in the output energy per pulse and in the average power output of the neutral Ba cyclic metal vapor laser as a function of the pulse repetition rate have been analyzed. At constant input power, the output energy per pulse is found to vary inversely as the two-thirds power of the pulse repetition frequency and so the average output power varies as the pulse repetition frequency to the one-third power up to the point where the Ba metastables do not have sufficient time to relax between pulses. Since the experiments which have been analyzed were conducted with a constant value for the laser discharge capacitance, these results imply that the output energy per pulse of this laser varies as the four-thirds power of the input voltage.     

1550nm单频脉冲光纤激光放大器实验研究

为了满足相干探测技术对激光光源的需求,采用主振功率放大技术,对全光纤、高重复频率、1550nm单频脉冲光纤激光器进行了研究.得到了脉冲宽度400ns、重复频率10kHz、单脉冲能量14μJ、平均功率148mW的单模光纤激光脉冲输出.实验中还发现了光纤中过高的功率密度所引起的受激布里渊散射(SBS)将导致激光脉冲波形的变...     

用于白癜风治疗的308nm XeCl准分子激光系统

研制了一台用于白癜风治疗的308nm XeCl准分子激光系统。根据准分子激光器脉冲式放电的特点,设计了推挽式脉冲开关电源。实验研究了激光器脉冲重复频率、工作电压、气体寿命对激光输出能量的影响,并检测了激光输出脉冲能量的稳定性。通过自动反馈控制系统调整激光头放电工作电压实现输出激光能量的稳定。激光采用扩展型紫外液芯光纤传导,得到均匀性良好的治疗光斑,液芯光纤对308nm激光的传输效率约为70%。激光器脉冲重复频率1～200Hz,工作电压18～25kV,输出能量不稳定度小于4%。经光纤输出用于治疗的有效光斑直径22mm,脉冲能量密度2～3mJ/cm2。     

Influence of the active zone diameter, on the UV-ion Ne-CuBr laserperformance

An active-zone-diameter scanning of an ultraviolet (UV) Cu⁺ laser excited in a nanosecond, pulsed longitudinal Ne-CuBr discharge with an excitation pulse repetition frequency of 19.5-25 kHz is carried out. The discharge conditions for achieving a maximum average output power on the UV lines-248.6, 252.9, 260.0, and 270.3 nm are found for each active zone diameter. A record average output power of 1.3 W is obtained for multiline operation. The specific average output power is 57 mW/cm³ at an active volume of 23 cm³. The highest peak pulse power and average laser power on the 248.6-nm laser line for the UV Cu⁺ lasers are also measured-3.25 and 0.85 W, respectively. A simplified kinetic model, which describes the discharge afterglow processes, is made     

用单片机实现脉冲固体激光电源双路输出

本文简要介绍了脉冲固体激光电源的组成 ,通过对放电回路的改进 ,实现了一个电源两个放电回路的交替工作。在泵浦电压 10 0 0V ,重频 2 0Hz,双路Cr,Tm ,Ho :YAG激光器光纤末端输出功率 2 2 .7W。     

High-repetition-rate operation of a segmented hollow-cathode Ne-Cu+ 249-nm laser

A segmented hollow-cathode Ne-Cu⁺ 249-nm laser is operated at a pulse repetition rate of 500 Hz and a pulse duration of 30 μs. The laser pulse has a risetime of 5 μs and is delayed by 5 μs on the leading edge of the current pulse. The fast evolution of the laser pulse results from a higher gas temperature at the start of each discharge pulse, and consequently during the pulse, due to the higher mean cathode temperature required to transfer the discharge power from cathode to anode. The higher gas temperature results in a faster diffusion of the sputtered copper atoms into the negative glow and in an increased rate coefficient for charge transfer, both of which increase the pumping rate for the laser transition. An initial overshoot in the discharge voltage gives rise to a sharp initial peak in the laser pulse. A significant sharp peak in the laser pulse immediately at the end of the current pulse indicates that an enhanced laser pulse of duration 10 μs at a pulse repetition rate of 1 kHz may be achieved by appropriately shortening the current pulse duration     

Compact long-life high PRF 722.9 nm neutral lead vapor laser

Several new construction techniques for a compact long-life high pulse-repetition frequency (PRF) 722.9 nm neutral lead vapor laser are described. A quartz discharge envelope, coaxial oven, and controlled semiself-heating techniques were employed. An average laser output power of 90 mW at a pulse repetition rate of 5 kHz has been obtained with a discharge efficiency of 0.03 percent.     

高峰值功率重频脉冲固体激光器

综述了高峰值功率重频脉冲固体激光器的发展现状，对其中的Ｑ开关、腔倒空、锁模等窄脉冲技术和放大技术进行了分析，展示了高峰值功率重频脉冲固体激光器的发展前景。     

基于三硼酸锂晶体高功率紫外脉冲激光器

为了获得高功率、高重复频率的紫外脉冲激光器,采用1064nm基频光通过三硼酸锂（LBO）晶体与3次谐波355nm进行和频得到4次谐波266nm紫外激光的方法,进行了实验验证,取得了重复频率为20kHz、紫外激光器的平均输出功率为2.5W、红外到紫外的转换效率为12.5%的实验数据。结果表明,此脉冲激光器利用LBO晶体在高重复频率下取得了较大的紫外平均输出功率。     

A frequency stabilized compact high repetition rate TEA-CO2laser

A compact atmospheric-pressure hybrid CO2laser utilizing a transverse double-discharge technique has been constructed and operated at moderate repetition rates. A pulse output energy of 80 mJ has been obtained under single-mode conditions at repetition frequencies of 100 Hz. Using the hybrid technique to obtain single-longitudinal-mode operation, we have been able to reach a 7 kHz long-term relative frequency instability between the TEA laser and a local oscillator. Measurements of the frequency sweeping during the pulse tail (chirp) are also presented along with a direct measurement of the resonant frequency pulling effect associated with the real part of the electric susceptibility of the gas. Limitations on the pulse repetition frequency for this laser configuration are also discussed.     

1550 nm全光纤单频脉冲光纤激光器

设计并实现了一种基于人眼安全波段的1550 nm全光纤化结构单频脉冲光纤激光器。激光器采用外腔稳频技术的单频半导体激光器作为种子源,其线宽1.8 kHz,功率20 mW。通过预放大器和声光调制器获得单频脉冲激光,并运用两级光纤放大器实现了线宽1.9 kHz、平均功率521 mW、脉冲宽度200 ns、重复频率10 kHz的单频脉冲光纤激光输出。输出脉冲峰值功率达260 W。输出端采用了双包层单模光纤,保证了输出激光的光束质量。整个激光器通过对种子光级联放大,结合放大器的增益控制,成功抑制了受激布里渊散射(Stimulated Brillouin Scattering,SBS)效应,消除了放大过程中噪声对线宽的影响,获得了线宽稳定的单频脉冲激光。     

Sealed, miniaturized, corona-preionized, high-repetition-rate TEA CO2laser using hydrogen buffered gas mixtures

Sealed-off operation of a compact, corona-preionized, TEA CO2laser capable of efficient laser action at pulse repetition frequencies of up to 1 kHz is reported. By adding hydrogen to the basic gas mixture we have been able to maintain discharge stability and constant average output power for more than 20 million laser shots at a 400 Hz repetition frequency with peak powers in excess of 350 kW.