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1.
根据高功率激光装置中强激光束传输的特点,建立了描述光束通过光学元件时引入的局部波前畸变模型,并利用纹波传输的线性化处理方法,研究了带有局部波前畸变的高强度光束的传输规律。以一个连续的非增益激光介质为例,用该模型进行数值模拟,给出了不同空间尺度的局部波前畸变的频谱分布、不同空间频率的纹波引起的振幅非线性增长曲线、不同B积分的非线性增益随光束传输距离的变化曲线,光束振幅非线性增益达到最大时光束的传输距离和标准传输距离不同时由局部波前畸变引入的振幅分布。研究表明为了防止光学元件损坏,应避免光学元件表面出现半径为0.5~2.0 mm的局部瑕疵。 相似文献
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体光栅光谱组束是获得高功率激光输出的一种有效途径.在有限的可用带宽内,光谱通道间隔影响着组束光束数目以及最终的高功率组束输出.采用耦合波理论,建立了一个两通道高功率光谱组束模型.通过优化体光栅光谱通道间隔,可放宽对组束子束线宽和功率的限制,组束功率可大幅提升而光谱密度并无显著下降.基于此,实验上获得了2.5 kW组束输出,绝对效率超过85%,通道间隔5 nm,光谱密度为0.51kW/nm.组束功率1 kW时,组束输出能保持好的光束质量;组束功率1.5kW时光束质量恶化较明显,通过分析发现,组束光束质量的恶化主要受限于体光栅的色散及高功率下体光栅复杂的热畸变. 相似文献
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Optical properties of Cr,Yb:YAG, Cr,Nd:YAG crystals, and composite Yb:YAG/Cr:YAG ceramics self-Q-switched solid-state laser
materials are presented. The merits of these self-Q-switched laser materials are given and the potentials of such lasers can
be chosen by the applications. Cr,Yb:YAG and composite Yb:YAG/Cr:YAG ceramics self-Q-switched laser are conducted. Although
several tens of kW peak power can be obtained with a monolithic microchip Cr,Yb:YAG laser, the experimental results show that
the performance of this laser is limited by the absorption of Cr4+ ions at a pump wavelength of 940 nm and strong fluorescence quenching at high Cr concentration. Composite Yb:YAG/Cr:YAG ceramics
are more suitable to realize high pulse energy and peak power (up to MW level) with optimized lasing and Q-switching parts.
In addition, the instabilities induced by the multi-longitudinal mode competition in Cr,Nd:YAG and Cr,Yb:YAG microchip lasers
are addressed. The different gain bandwidths of Yb:YAG and Nd:YAG play an important role in the instability of the output
laser pulse trains. Stable laser pulses from the Cr,Yb:YAG microchip laser were obtained due to the antiphase dynamics. For
the Cr,Nd:YAG microchip laser, the instability caused by the multi-longitudinal mode competition is an intrinsic property.
Different transverse patterns were observed in Cr,Nd:YAG microchip lasers when a pump beam with larger diameter was used.
Saturated inversion population distribution inside the gain medium plays an important role in the transverse pattern formation.
Different transverse patterns were reconstructed by combining different sets of the Hermite-Gaussian modes. 相似文献
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The lasing condition and frequency stability of the single longitudinal mode oscillation of a diode laser pumped 2 μm Tm,Ho:YLF microchip laser at room temperature are reported. It is shown that the microchip laser with an output mirror of 99.0% reflectivity had better single longitudinal mode performance than that with an output mirror of 99.5% reflectivity. The frequency tuning rate when varying the crystal temperature was estimated to be 1.9 GHz/°C. Frequency stability of the microchip laser is examined by the self-beating heterodyne detection method for several delay times between 0.48 and 4.8 μs. It is indicated that the spectral fluctuation is in proportion to the delay time and the increasing rate is 2.3 kHz/μs. 相似文献
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在高功率光纤激光器中, 增益光纤的热效应是限制激光功率进一步提高的重要因素之一. 为了降低增益光纤的最高温度, 提出了一种通过改变增益光纤的掺杂浓度分布, 分散光纤激光的热效应, 从而提高激光输出功率的方法. 基于速率方程模型和热传导模型, 在光纤激光放大器输出功率大致相当的情况下, 对几种不同掺杂方式下增益光纤中的热分布和放大器的输出功率进行了数值模拟. 研究结果表明: 增益光纤的梯度掺杂可以优化光纤中的温度分布并提高光纤熔接点的稳定性; 同时兼具提高输出光束的光束质量、抑制光纤中非线性效应和模式不稳定的效果, 是提高光纤激光放大器输出功率切实可行的办法. 研究结果可以为高功率光纤激光器中增益光纤的设计提供一定的参考. 相似文献
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M. M. El-Nicklawy M. A. Kenawy M. M. H. Elnaby A. F. Hassan A. A. Hemida 《Czechoslovak Journal of Physics》1989,39(9):998-1006
The formulas of the dependence of the spectral laser power distribution and its spectral half-width on the physical parameters of its laser active medium are derived. In addition it is found that, if the gain line profile has a Lorentzian or Gaussian distribution, the spectral laser power distribution is of a Lorentzian profile. The spectral halfwidth of the laser beam in both cases are slightly different form each other. For a general gain line profile, the spectral laser power distribution behaves as a differential form like that of the gain line profile.The spectral halfwidth of He/Ne laser beam having powers (0·5 mW, 1·0 mW, 3·0 mW and 50 mW) and that of their longitudinal modes, the laser gain factor and the difference between the population atomic densities of the upper and lower energy levels for the laser line transition are experimentally determined. 相似文献
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Longhi S 《Optics letters》2011,36(5):716-718
It is theoretically shown that an end-pumped microchip laser formed by a thin laser crystal with plane-plane but slightly tilted facets can emit, under appropriate pumping conditions and near a crystal edge, a truncated self-accelerating Airy output beam. 相似文献
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An antiresonant ring (ARR) interferometer configuration is introduced for the characterization of a continuous wave (CW) Nd:YAG laser output. The output of the ARR device is precisely characterized todetermine the gain and loss of a laboratory CW Nd:YAG laser by using the Findlay-Clay approach. TheARR arm is then experimentally arranged inside the cavity of an arranged high power side-pumped CWNd:YAG laser. A coated beam splitter with 50–50% reflectivity at normal incidence is placed inside thecavity to provide a wide range of reflectivity from 0 to 100%. This is performed by a rotatable stage and tilting the beam splitter by 10°with the steps of 0.05. By changing the input electrical power of the laser pump the variation of the output laser power is monitored for 20 individual reflectivity of ARR arm.Average pump threshold power of about 180 W is obtained. With the help of the derived equations and obtained threshold power, small signal gain and loss associated with the emerging beam is estimated. It is verified that the former is very dependent to the input parameters. Laser efficiency is also measures 5.6% which is quite comparable with the reported values. 相似文献
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The beam quality of the laser beams after spectral beam combining (SBC) has been analyzed in this paper. Based on the propagation model of the spectral beam combining system, the expression for the output field of an individual beam passing through the spectral beam combining system with lens aberration has been given and the intensity distribution of the combined beam has been studied by the principle of incoherent superposition. Consequently, according to the intensity second-order moments method, the M2-factor of the combined beam has been calculated and the effect of lens aberration on the characteristics of the combined beam has been analyzed quantitatively. It can be shown that the SBC system can improve the beam quality of laser array significantly, and the M2-factor of the combined beam passing through the ideal spectral beam combining system is almost the same as that of an individual beam. For the spectral beam combining system with lens aberration, the spherical aberration has greater effect on the off-axis beam than on the on-axis beam, and the beam quality of combined beam degrades with increase in lens aberration. 相似文献
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C.P. Wyss W. Lüthy H.P. Weber V.I. Vlasov Y.D. Zavartsev P.A. Studenikin A.I. Zagumennyi I.A. Shcherbakov 《Applied physics. B, Lasers and optics》1999,68(4):659-661
4 as a host for neodymium has several advantages for diode pumping in comparison with other crystals. The absorption cross
section of neodymium in GdVO4 is considerably stronger and broader than in YAG. This allows for the construction of very compact monolithical microchip
lasers. In our paper, we report for the first time on a diode-pumped monolithical Nd3+([%at.]1.3):GdVO4 microchip laser at 1.06 μm. A maximum output power of 5 W is achieved. The temporal and the spectral emission properties
are described. The beam propagation properties are studied in detail.
Received: 23 July 1998 / Revised version: 9 November 1998 / Published online: 24 February 1999 相似文献
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多纵模高光谱分辨率激光雷达是一种新型的高光谱分辨率激光雷达.本文在研究典型高功率Nd:YAG脉冲激光器的多纵模模式及其在大气中传输的气溶胶米散射和瑞利散射光谱的基础上,设计紫外域多纵模高光谱分辨率激光雷达系统,采用窄带干涉滤光片滤除太阳背景光的影响,设计可调谐马赫-曾德尔干涉仪,分离提取多纵模激光回波中的气溶胶米散射和瑞利散射光谱,并利用马赫-曾德尔干涉仪双通道输出的互补性原理,精确反演气溶胶光学参量.系统仿真结果表明,所设计的紫外域多纵模高光谱分辨率激光雷达能够实现10 km高度内的气溶胶光学参量精细探测. 相似文献
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本文介绍了一种用波长为809nm的激光二极管(LD)端面泵浦厚度为1mm的微片Nd:YVO4全固化固体激光器。器件结构上采用了一种独特的光学系统,该系统由分别用于LD激光束的耦合和聚焦的两部分组成。由Nd:YVO4的一个平面与一个曲率半径为21mm的球面镜组成半共焦腔,以获得高的转换效率。文中详细讨论了单横模运转时的泵浦光与激光腔模之间的匹配问题。当泵浦光功率为400mW时,获得152mW的1064nm波长的TEM00模激光输出。器件阈值功率为48.3mW,总的光-光转换效率为38%,斜效率为43%. 相似文献
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针对二维气体浓度分布,主要选用多条H2O的吸收谱线,采用代数迭代重建算法,研究了在激光光束较少且假定温度分布已知的情况下,即不考虑燃烧场中温度对谱线强度的影响时,不同谱线条数对二维浓度重建结果的影响,对比了在同一浓度模型下通过增加激光光束与增加H2O吸收谱线条数对气体浓度重建结果的影响;研究了增加谱线条数重建气体浓度分布对不同温度与浓度分布模型的适应情况,其中,文中所选取的多条吸收谱线可以由一个激光器同时扫描得到。浓度测量区域采用10×10的网格划分,测量区域中的温度和浓度分布采用单峰不均匀分布与双峰不均匀分布,重建过程中计算了吸收谱线与激光光束的有效利用率。重建结果表明在激光光束较少时,增加吸收谱线条数可以获得更多与浓度相关的谱线参数信息,且与增加激光光束相比可以明显改善浓度重建结果,更主要的是增加谱线条数可以有效降低实验中硬件设备的成本投入以及测量系统的复杂性。 相似文献
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In this paper, we model and analyze thermal focusing effect in the microchip lasers pumped by vertical-cavity surface-emitting lasers (VCSELs) for a special pump scheme, in which the microchip is axially connected with the VCSEL pump source without a gap between them to form a sort of ultra-compact monolithic micro-lasers. Thus, the thermal effects are related to twofold heating processes in the microchip. One is the common pump beam heating. The other is the heat flux diffusion from VCSEL to microchip through the contact interface between both, the latter leads to different thermo-optic characteristics from that generated only by the pump beam heating in the microchip. The temperature-, the stress- and the expansion-related phase variations and thus the thermal focusing properties of the microchip regarding the twofold heating processes are calculated and discussed for various pump power densities and temperatures of the VCSEL using analytical models. The results show that both heating processes in such a pump configuration can produce comparable thermal effects to each other. The influence of the heat transfer from the VCSEL to the microchip laser performance is discussed as well. 相似文献