共查询到20条相似文献,搜索用时 93 毫秒
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采用量子理论讨论共振简并双光子激光的小偏谐近阈行为,在一定条件下,系统能够呈现无反转激光,在另一条件下,系统则以于现无激光反转。 相似文献
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类锂硅离子软X射线激光研究 总被引:1,自引:0,他引:1
在激光等离子体典型参数条件下,利用碰撞-辐模型计算了类锂硅离子5f-3d和4f-3d跃的粒子数反转比率和激光增益系数。讨论了不同热带条件和不同冷却速度下,激光增益系统数的变化。计算结果表明,高功率,短脉冲激光生产的高温等离子体在快速冷却条件下能产生软X射的线激光增益。 相似文献
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以简单的火花间隙作为放电开关,建立了一种用于ps脉冲激光放大的大口径放电泵浦KrF准分子激光器。该激光器的有效增益口径截面为4cm×3cm,在自由运转情况下最大激光输出能量为1.3J,脉宽20ns。用作ps放大器时,利用光学偏振放大方式获得了激光能量140mJ,脉冲宽度10ps的激光输出。利用XeCl激光泵浦的染料激光作为探针测量了不同放电条件下和不同气分比条件下激光的增益和吸收系数。 相似文献
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在LF-11和LF-12高功率激光装置上进行的实验中,设计了一些特定的激光束-金腔靶-探测器条件,创造了激光直接加热、准辐射加热和激光、X光混合加热三种物理条件,采用软X光透射光栅能谱时空分辨技术,测量了腔靶、缝靶和双孔靶等高分辨X光能谱,研究了激光等离子体X光辐射非平衡特性。 相似文献
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基于条纹管激光成像的基本原理,分析了利用条纹管实现紫外到近红外波段激光成像的技术可行性,并对其性能进行了分析;建立了激光成像雷达方程,计算了不同波长在不同天气条件下的探测距离,并分析了各激光波长的应用领域和优缺点. 相似文献
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用CO2,Nd:YAG和Cu蒸气激光分别对三种掺钕磷酸盐玻璃进行激光预辐照处理,研究了不同的激光波长的辐照条件对磷酸盐玻璃1.06μm激光破坏强度的影响。 相似文献
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Tanaka KA Hashimoto H Kodama R Mima K Sentoku Y Takahashi K 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(3):3283-3288
Hole boring characteristics of laser beams are studied using two different laser wavelengths in preformed plasmas with overdense regions. We have shown that a whole beam self-focusing is created in plasma with a considerable density scale length using a 1 microm wavelength laser. The whole beam self-focusing of this type could be used for guiding the ultrahigh intense laser pulse to a highly compressed core for studying the feasibility of a fast ignitor. There is a clear difference in the hole-boring characteristics between two laser wavelengths at 1053 and 351 nm, both in the experiment and the simulation. Using the third-harmonic laser, a whole beam self-focusing is never created. The 351-nm laser beam broke up into filaments resulting in plasma jets observed in our interferogram. 相似文献
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R. Heathcote M. Galimberti R. J. Clarke T. B. Winstone I. O. Musgrave C. Hernandez-Gomez 《Applied physics. B, Lasers and optics》2014,116(4):805-809
Modelling and analysis have been performed to show a link between laser collimation tolerances and dispersion effects in chirped pulse amplification (CPA) compressors. These show that an un-collimated beam can present itself as residual dispersion in a CPA system which uncorrected will have adverse effects on laser power and intensity. The techniques of shearing interferometry and beam propagation over large distances for setting beam collimation have been assessed for their limitations in measuring wavefront radii. An analysis of the sensitivity of CPA systems to non-collimated beams has been studied. This effect has been practically demonstrated for a high-power Nd:glass laser and the best techniques for alignment are discussed. 相似文献
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We have generated a frequency-modulated laser beam by use of cross-phase modulation between orthogonally polarized beams in a polarization-preserving optical fiber. This frequency modulation is based on the temporal intensity beating of the drive beam that is caused by another beam that has a slightly different wavelength. Moreover, we have demonstrated generation of a special frequency-modulated laser beam with temporally changing modulation frequency by use of cross-phase modulation in conjugation with self-phase modulation. 相似文献
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“之字形”光路薄管固体激光是一种结构紧凑、增益高且利于发射的新型激光光源。针对薄管固体激光光源及其大气长程传输过程中的光束质量退化问题,提出了基于直角锥面变形镜的薄管激光校正方法,进而通过建立薄管激光校正模型以及大气长程传输模型,开展了薄管激光大气长程传输光束质量分析。首先,针对大遮拦比窄环宽环形光束与发射系统的匹配问题,提供了一种薄管激光环形光束整形变换方案,有效实现了薄管激光的整形和变换。然后,分析了薄管激光光源光束质量、大气湍流效应和热晕效应等对整形变换后的薄管激光大气长程传输特性的影响,进而明确了薄管激光大气长程传输光束质量退化机理。最后,分析了直角锥面变形镜对薄管激光的光源畸变、大气湍流的低频分量和热晕导致的离焦相位等的校正效果。结果表明,经过直角锥面变形镜的校正,薄管激光光源光束质量明显改善,大气长程传输后的远场光束质量有所提高。若进一步配合常规变形镜进行联合校正,薄管激光大气长程传输后的远场光束质量可得到显著提升。 相似文献
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This work reveals an exploration of self-focusing of Hermite-cosine-Gaussian laser beam in a collisionless plasma under relativistic nonlinearity. Self-focusing along with self-trapping of Hermite-cosine-Gaussian laser beam are analyzed for different values of laser intensity, plasma density, and decentered parameters. Mathematical analysis displays that these parameters play a major role in achieving the stronger and earlier self-focusing. Further, a comparative study between self-focusing of Hermite-cosine-Gaussian laser beam with and without exponential density ramp profile is introduced. Plasma density transition with exponential profile is found to be more effective in order to have stronger self-focusing. The present analysis may lead to very useful applications in the field of efficient harmonic generation, laser driven fusion etc. 相似文献
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With a view to measuring the structure coefficient of refractive index fluctuations in a turbulent premixed butane-air flame, a thin laser beam is sent into the flame perpendicular to the flow direction. The laser beam generally undergoes fluctuations of direction, phase, and amplitude. Only the random deflections of the laser beam may be taken into account. After having traversed the flame, the perturbed laser beam enters into an interferometric system. Materials and experimental procedure are described. In the unperturbed interference pattern, the zones only sensitive to fluctuations of the angle-of-arrival of the laser beam are detected. From the random displacements of the central bright fringe, the structure coefficient of refractive index fluctuations in the flame is measured. To prove that the method of measurement is satisfactory, the result obtained is applied for computing the power spectral density of the angle-of-arrival of the laser beam from the formula of correlations of the laser beam deflection angles which we have demonstrated in previous works. This computed power spectral density is compared to that measured from the effective position of the detector. A good agreement is observed between the two results. 相似文献
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双折射双频激光器输出光偏振特性的实验研究 总被引:7,自引:2,他引:5
报道了双折射双频激光器输出光偏振特性的实验研究,实验发现双折射双频激光器两端输出的线偏振光的偏振方向并不一致,而相互有一定的旋转角度,实验也再次证明了激光器输出的是正交线偏振光,而不是晶体本征模的椭圆化了的偏振光。 相似文献
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线阵激光二极管侧面抽运Nd∶YAG激光器特性研究 总被引:1,自引:0,他引:1
依据四能级系统速率方程 ,推导出了多横模振荡固体激光器输出与输入参量的关系。对二极管抽运固体激光器中线阵激光二极管三向对称侧面抽运结构 ,计算了抽运光强分布 ,并就激光器的阈值抽运功率、近阈值条件下的斜率效率、输出功率和光束质量等与抽运参量的关系 ,进行了数值计算。由计算结果看出 ,线阵激光二极管侧面抽运Nd∶YAG激光器中晶体半径和抽运光束腰半径是影响输出激光功率和光束质量的主要因素 ,并通过在谐振腔中加小孔选模 ,使光束质量得到明显改善。选择了一组三向侧面抽运结构参量进行了实验验证 ,实验结果与理论计算一致。 相似文献