One watt average power by second harmonic and sum frequencygeneration from a single medium scale copper vapor laser

Ultraviolet (UV) powers of over 1 W have been obtained by second harmonic and sum frequency generation from a single medium scale (20 W) copper vapor laser (CVL) using a new focal geometry in which the CVL beam is focused in only one direction to produce a line focus within a BBO crystal. High optical conversion efficiencies, 20 and 30%, are observed for the low divergence (~-10 times the diffraction limit) and diffraction-limited components of the CVL output, respectively. Wall-plug efficiencies for UV generation are up to 0.04%. Efficient frequency conversion has also been demonstrated for CVL operating conditions unsuited to the generation of diffraction limited output     

用自滤波及注入锁定提高铜蒸气激光在BBO晶体中的倍频效率

本文采用自滤波非稳腔振荡和注入锁定放大的铜蒸气激光系统,获得了发散角为0.22mrad,偏振度为93％,510.6nm线输出功率为9.2W的激光束。将这一光束聚焦到长9mm的BBO晶体中,获得了1.2W的倍频光,其转换效率为13％,当移去滤波小孔后,所产生的倍频效率下降到8％。     

铜激光光脉冲的时间特性

测量了铜激光两种波长510.6nm和578.2nm光脉冲的抽运时间与氖压和充电电压间的关系。波长578.2nm的光脉冲的抽运时间在不同氖压下随电压的增加而缩短。波长510.6nm光脉冲的抽运时间与电压的关系对氖压较为敏感。     

铜蒸气激光器的改进及稳定

通过改变放电管中铜粒的位置、放电管外层保温材料的性质和厚度以及对放电产生的电磁辐射进行屏蔽等措施,进一步提高了25W铜蒸气激光器的可靠性和稳定性。     

40W铜蒸气激光器的研究

I.Smilanski和Anderson、B.E。Warner等人在大口径器件上首次实现了平均输出功率20W以上的铜蒸气激光器的运转,证实了利用管径比例法可以实现60W以上的铜蒸气激光功率输出。由于铜蒸气激光器脉冲重复频率高(5～15kHz),发射波长为绿色(510.6nm)和黄色(578.2nm),短脉宽(～30ns),使它在激光分离同位素铀、燃烧研究、水下研究,摄影术和全息术、半导体制造、指纹检测、医疗等方面都有重要的应用潜力。本文报道40W铜蒸气激光器的研究结果。     

Afterglow ground-state copper density behavior in kineticallyenhanced copper vapor lasers

The interferometric “Hook” method has been used to measure the copper ground-state density during the interpulse period for a 38 mm bore diameter copper vapor laser (CVL) operated in kinetically enhanced (KE) mode (Ne-HCl-H₂ gas mixture) and in conventional mode (pure neon and Ne-H₂ gas mixtures). It was found that the rate of regrowth of the axial copper density during the afterglow of the KE-CVL is 3-4 times faster, and the axial prepulse ground-state copper density is 2-3 times higher, than that observed for pure Ne or Ne-HI buffer gases. We conclude that the primary action of the HCl+H₂ additives is to increase the interpulse plasma relaxation rate and to increase the threshold copper density beyond which thermal runaway occurs. These effects are primarily responsible for the elevated pulse rates and increased pulse energies giving improved power scaling characteristics of KE-CVLs     

Computer simulated rate processes in copper vapor lasers

A computer model for metal vapor lasers has been developed which places emphasis on the change of excited state populations of the lasant through inelastic collisions and radiative interaction. Also included are an energy equation for the pumping electrons and rate equations for laser photon densities. Presented are results of calculations for copper vapor with a neon buffer over a range of conditions. General agreement with experiments was obtained.     

铜蒸气激光器放电回路元件的最佳化

用计算机对铜蒸气激光器放电回路元件的最佳值进行了数值求解。适当选择锐化电容和回路电感量,可以使放电电流脉冲变窄而又不加重闸流管的负担。     

宽带激光二倍频特性的理论分析

在激光核聚变(ICF)物理实验中,采用相干度较小的宽带倍频激光,能有效抑制高阶非线性效应和提高靶的激光辐照均匀性。根据不同频率成分和频耦合原理,建立了宽带二倍频转换的物理模型,作了理论计算分析,发现二倍频光的光谱变窄,结果对宽带三倍频研究具有一定应用价值。     

Fast optical shuttering and wavelength selection in copper vapor lasers and copper bromide lasers by intracavity polychromatic acoustooptic modulation

We propose a fast effective intracavity technique for optical shuttering and wavelength selection in copper vapor lasers and copper bromide lasers by inserting a polychromatic acoustooptic modulator in a low-intensity section of a classical negative branch unstable resonator. Single-pulse or multiple-pulse operation in one- or two-wavelength emission was achieved in a CuBr laser system. The spatial distributions of the output laser beam as recorded by a CCD camera showed neither power losses nor worsening of the beam quality in comparison with the classical scheme without the modulator. The laser output was characterized with a high degree of linear polarization.     

聚焦对二次谐波转换效率的影响

利用KTP晶体,腔外倍频1.0795μmTEM00模Nd:YAP激光,在实验上研究了二次谐波转换效率随聚焦透镜的焦距及晶体位置变化而变化的规律。结果表明:给定的晶体,存在一个最佳聚焦条件及最佳的晶体位置。     

Enhanced carrier injection efficiency from lateral current injection in multiple-quantum-well DFB lasers

A bidimensional simulation shows that the lateral carrier injection in etched active region of multiple-quantum-well DFB lasers represents a large fraction of the injected current, leading to improved carrier homogenization in the wells. This increases the average carrier density substantially and provides a much higher gain for the same injected current, depending on detailed device structure.     

Phase matching limitations of high efficiency second harmonic generation

-A discussion of second harmonic generation with imperfect phase matching in the high conversion limit is presented. Phase modulation of the fundamental pulse, dispersion, central frequency wavevector mismatch, and fundamental depletion are included. The results show that even small amounts of phase modulation or central frequency wavevector mismatch can limit harmonic generation and must be considered at high conversion efficiency. Both spatial and temporal phase matching parameters are more restrictive at high conversion efficiency because of the narrowing of the central phase matching peak. If the harmonic conversion process is overdriven, severe distortion of the harmonic and transmitted fundamental pulses can result. Cascade harmonic generation of neodymium laser radiation to 266 nm is presented as an example.     

铜蒸气激光器加宽放大及双程放大的输出特性

在铜蒸气激光器振荡-放大系统中采用加宽脉宽放大以及双程放大技术,其输出功率能比未加宽时行波放大的输出功率分别提高7％和8％,铜蒸气激光放大器的输出光波形相对于输入光波形的抖动量为±4.0ns,而两台振荡器之间光波形的抖动量为±9.0ns。     

High power efficient dye amplifier pumped by copper vapor lasers

An extensive study has been performed on a dye amplifier pumped by copper vapor lasers. The amplifier utilizes a transverse pumping configuration in which the dye flow, pump beam, and dye extraction beam are mutually orthogonal. The operating characteristics of the amplifier have been studied using four dye-solvent systems which span the wavelength range continuously from 560 to 690 nm. Optimum conversion efficiencies of 18-30 percent at output powers of 0.41-0.76 W have been measured from the four dyes at a 6 kHz pulse repetition rate. The efficiencies and output powers were limited only by the available copper laser pump power. Analytic expressions have been obtained for the amplifier power gain and efficiency using a rate equation treatment of the system dynamics. Excellent agreement is obtained between the predicted and measured amplifier gain characteristics for rhodamine 6G.     

用于铜蒸气激光器的可饱和电抗器

给出用于铜蒸气激光器的可饱和电抗器的设计考虑.实验表明,可饱和电抗器的应用改善了闸流管的开关特性,增加了脉冲重复率和输入的电功率.     

高效宽带二倍频激光原理及实现方法

利用两块Ⅰ类KDP倍频晶体级联的方式,研究了时间相位调制宽带激光的二倍频特性.实验获得了二倍频转换效率与入射基频光功率密度的关系,在基频光功率密度为1.6 GW/cm2时,最大二倍频转换效率达70％,接近理论模拟的结果.实验结果表明,在高功率密度和低功率密度基频光条件下,倍频光光谱宽度约为入射基频光带宽的一半,与理论计...     

Power conversion efficiency in second harmonic generation withnonuniform beams

The efficiency of nonlinear optical conversion of fundamental to second harmonic power is analyzed for beams with arbitrary super-Gaussian shapes in time and/or space. A convenient change of variables is used to simplify the computational aspects of the problem and the number of free parameters. This transformation is used to generate nondimensional efficiency curves for both single- and two-crystal cascaded doubling schemes (e.g. quadrature schemes). Data are generated which enable the determination of optimal magnification/demagnification of the beam for high conversion efficiency. The results are a useful guide to the design of practical doubling arrangements, and reveal in a quantitative manner the differences between frequency doubling with spatially and temporally flat beams and doubling with the nonuniform beams more usually encountered in practice     

铜蒸气激光链中激光脉冲的抖动分析

运用概率论方法导出了铜蒸气激光链中激光脉冲抖动量的表达式,结果表明:当铜蒸气激光器并联时,两台激光器输出光脉冲之间的抖动量的平方等于每台激光器输出光脉冲相对于电触发脉冲抖动量的平方和;当多台铜蒸气激光器串联放大时,第m台激光器输出光脉冲相对于振荡器输出光脉冲的抖动量随m的增加而增加,但总是小于每台激光器放电脉冲抖动量的2~(1/2)百倍。实验结果与理论计算基本相符。     

Comparison of copper acetylacetonate, copper (II) acetate, and copper chloride as lasants for copper vapor lasers

The operating characteristics of a neutral copper laser oscillating on the 5106 Å transition employing copper acetylacetonate, copper (II) acetate, and copper chloride oscillating on the 5106 and 5782 Å are described; and all three laser systems are compared in a fixed parameter system. The total output energies for optimum temperature, buffer gas pressure, dissociation pulse energy, and time delay were measured for each laser system. The total energies for the three lasants Cu(Ac)2, Cu(Ac), and CuCl under optimum lasing conditions are in the ratio of 3:2:1.