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为了将虚共焦非稳腔输出光束质量高和角锥棱镜谐振腔具有免调试的优点结合到一起,提出了用球面角锥棱镜构成虚共焦非稳腔的方案。利用已有虚共焦非稳腔钕玻璃激光器,设计加工了一球面角锥棱镜非稳腔钕玻璃激光器。模拟计算了两谐振腔输出光束的模式分布,然后对两钕玻璃激光器进行了实验对比研究。结果表明:实验得到的模式分布与模拟计算结果相吻合,球面角锥棱镜非稳腔钕玻璃激光器与虚共焦非稳腔钕玻璃激光器分别获得了最大2176.9J和2340.6J的能量输出,二者的电光效率与束散基本相同,分别为4.3%,0.30mrad和4.6%,0.26mrad。 相似文献
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对Du Fort-Frankel差分格式用于谐振腔模式计算进行简要分析,以该差分格式为基础,提出基于移动矩阵法的非稳腔模式数值计算快速算法.对空腔共焦非稳腔模式进行数值模拟,将计算结果与参考文献进行对比,两者吻合较好.对有源共焦非稳谐振腔内增益区位置对谐振腔输出功率的影响进行数值计算,结果表明:对于采用共焦非稳腔的大功率激光器,当增益体积一定、小信号增益曲线相同时,随着谐振腔内增益区与凹面镜之间的距离的减小,激光器输出功率会有较为明显的提高.数值算例证明了本文方法的正确性和有效性. 相似文献
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对半导体抽运的Yb∶YAG克尔透镜锁模激光器进行理论分析计算,分析五镜谐振腔和四镜谐振腔的稳区不同,利用稳区范围变化对五镜谐振腔稳定锁模机理做出合理解释.详细计算分析Yb∶YAG激光器内克尔调制效应对锁模的影响,获得最佳腔参量.在腔内没有插入硬光阑的情况下,利用五镜腔实现了Yb∶YAG晶体克尔透镜锁模运转.理论分析和实验结果相符. 相似文献
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本文通过菲涅耳-基尔霍夫衍射积分方法,推导了一般稳定和非稳定球面镜谐振腔中自再现模的解析表达式,揭示了从稳定腔变为非稳腔过程中自再现模的变化规律.进一步地,本文在几何光学近似条件下得到了非稳腔的自再现模,通过与衍射积分结果对比,发现基于几何光学近似得到的非稳腔最低阶偶对称模(即基模)和最低阶奇对称模的空间分布与衍射积分结果一致.而对于更高阶的自再现模,当非稳腔接近稳定腔时,几何光学近似得到的自再现模空间分布和衍射积分结果之间存在较大差异.本文的结果可以作为激光原理教学内容的重要补充. 相似文献
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分析了角锥棱镜对光束的相位变换作用,带二面角误差的角锥棱镜可等效于6块光楔的组合,其楔角的大小和方向由二面角误差决定。对在腔内往返传输的光线在镜面上的位置进行了分析,结果表明:3个二面角误差相同且不为零的角锥棱镜构成的谐振腔为约束非稳腔。用Fox-Li迭代法数值模拟得到了不同棱镜二面角误差情况下的谐振模式。模拟结果表明:圆形镜腔情况下基本振荡模式接近于TEM03模的拉盖尔高斯光束;当3个二面角误差不相同时,模式中各个区域的强度分布不对称。采用3个二面角误差基本接近且绝对值较小的棱镜可以提高光束质量。 相似文献
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激光谐振腔设计软件的算法研究与计算机实现 总被引:1,自引:1,他引:0
为使激光工作者可以方便地进行谐振腔诸如热透镜、容差等参量的优化分析与设计,研究了激光谐振腔设计软件的算法并在计算机上得到实现.使用ABCD矩阵方法分析激光光束的传输与变换.为使分析和设计更具有一般性和通用性便于计算机编程,考虑矩阵元素均为复数的情况,同时将光束质量因子M2和介质中的光束传输考虑在激光谐振腔模的传输变换当中,这样当矩阵元素虚部都为零,而M2=1和介质折射率为1时,就可以过渡到通常的基模高斯光束在空气中经实元件矩阵传输变换.并以此为基础使用VB在国内成功开发出具有稳定驻波腔、稳定行波腔、非稳驻波腔、非稳行波腔、相位共轭腔、光束传输变换等多种功能的可视化谐振腔软件. 相似文献
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应用Monte Carlo方法,对能量E0≤5keV低能电子作用下固体Al、Cu、Ag、Au的背散射电子发射及表面空间分布作了计算.模型应用Mott散射截面及修正的Bethe方程分别描述低能电子在固体中的弹性和非弹性散射.计算了背散射电子能量分布、表面空间分布、深度分布和角分布规律及特征,还计算分析了背散射电子角分布与深度分布、表面空间分布及能量分布之间的关系,系统地描述了背散射电子的发射及分布规律. 相似文献
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针对北极冰下双声道波导的噪声分布特性研究,采用垂直阵对双声道波导内的噪声场进行了观测,北极冰下噪声物理模型使用混合加性噪声模型描述,统计分布模型使用α稳定分布描述.并将噪声划分为3个频段,按噪声来源分为背景噪声、冲击噪声以及航船噪声3种场景,分析其统计特性,给出了直方图统计、核函数估计与正态分布的比较结果,α稳定分布参数估计结果,峰度与偏度的计算结果以及累积分布函数检验结果。经分析讨论,给出结论:双声道波导中的噪声统计分布可用α稳定分布来描述,但上下表面声道的分布参数具有明显差别,上表面波导背景噪声明显偏离高斯分布而下表面声道的背景噪声接近于高斯分布;上下表面声道中不同频带的噪声分布差异也很明显,其中2~30 Hz差异性最大,30~100 Hz差异性较大,而100~500 Hz差异性相对较小,并且可以认为是对称α稳定分布.此外,上下表面声道中不同频带噪声α稳定特征参数变化也存在差异,上表面波导受冲击噪声影响α值变大,拖尾变薄;而下表面波导受冲击噪声影响α值则会变小,拖尾变重。 相似文献
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CHEN Zhi-Yuan ZHANG Duan-Ming ZHONG Zhi-Cheng LI Rui 《理论物理通讯》2007,47(6):1135-1142
We present a one-dimensional dynamic model of polydisperse granular mixture with the fractal characteristic of the particle size distribution, in which the particles are subject to inelastic mutual collisions and are driven by Gaussian white noise. The inhomogeneity of the particle size distribution is described by a fractal dimension D. The stationary state that the mixture reaches is the result of the balance between energy dissipation and energy injection. By molecular dynamics simulations, we have mainly studied how the inhomogeneity of the particle size distribution and the inelasticity of collisions influence the velocity distribution and distribution of interparticle spacing in the steady-state.The simulation results indicate that, in the inelasticity case, the velocity distribution strongly deviates from the Gaussian one and the system has a strong spatial clustering. Thus the inhomogeneity and the inelasticity have great effects on the velocity distribution and distribution of interparticle spacing. The quantitative information of the non-Gaussian velocity distribution and that of clustering are respectively represented. 相似文献
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采用离散元模拟研究成分无序颗粒体系中切向力的几率分布.将切向力分为主切向力和次切向力分别进行统计,结果表明主切向力与次切向力服从不同的分布.随着缺陷率的增加,主切向力由近似的正态分布变为双峰状的分布,最后变为单峰状的分布;而次切向力总是指数型分布.通过理论计算和模拟讨论了切向力分布,说明缺陷率较大的成分无序体系与结构无序体系有类似的力分布规律. 相似文献
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This study carried out a numerical simulation of electrostatic potential distribution in the cylindrical oil tank, focusing on spatial distribution of electrostatic potential and the variation tendency of the potential in the filling operation. Electrostatic potential distribution of stationary oil was illustrated, and the relationship between the electrostatic potential distribution and some parameters of the tank and oil was analyzed as well. Dynamic electrostatic distribution was studied when charged oil is filling into the tank, and ESD prevention measures’ effects on electrostatic potential distribution were simulated. Finally, calculation results of two other types of oil tanks were presented in brief. 相似文献
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By analyzing the Japan Meteorological Agency (JMA) seismic catalog for different tectonic settings, we have found that the probability distributions of time intervals between successive earthquakes-interoccurrence times-can be described by the superposition of the Weibull distribution and the log-Weibull distribution. In particular, the distribution of large earthquakes obeys the Weibull distribution with the exponent α1<1, indicating the fact that the sequence of large earthquakes is not a Poisson process. It is found that the ratio of the Weibull distribution to the probability distribution of the interoccurrence time gradually increases with increase in the threshold of magnitude. Our results infer that Weibull statistics and log-Weibull statistics coexist in the interoccurrence time statistics, and that the change of the distribution is considered as the change of the dominant distribution. In this case, the dominant distribution changes from the log-Weibull distribution to the Weibull distribution, allowing us to reinforce the view that the interoccurrence time exhibits the transition from the Weibull regime to the log-Weibull regime. 相似文献
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B. Waclaw Z. Burda W. Janke 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,65(4):565-570
We study statistical properties of a zero-range process (ZRP) on random networks.We derive an analytic expression for the
distribution of particles (also called node occupation distribution)in the steady state of the ZRP in the ensemble of uncorrelated
random graphs. We analyze the dependence of this distribution on the node-degree distribution.In particular, we show that
when the degree distribution is tuned properly, one can obtainscale-free fluctuations in the distribution of particles.Such
fluctuations lead to a power law in the distribution of particles, just like in the ZRP with the hopping rate u(m) = 1+b/mon
homogeneous graphs. 相似文献
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By introducing the thermal entangled state representation,we investigate the time evolution of distribution functions in the dissipative channels by bridging the relation between the initial distribution function and the any time distribution function.We find that most of them are expressed as such integrations over the Laguerre-Gaussian function.Furthermore,as applications,we derive the time evolution of photon-counting distribution by bridging the relation between the initial distribution function and the any time photon-counting distribution,and the time evolution of Rfunction characteristic of nonclassicality depth. 相似文献
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光纤耦合LD输出光场特性研究 总被引:1,自引:0,他引:1
根据光纤传输的模式理论,分析了单芯光纤输出端面的光场分布.利用单模光纤测量了纤端光场的强度分布,拟合了光纤输出端面光强分布的近似表达式.根据此数值计算和实验测量了多芯光纤输出端面的强度分布,结果基本吻合.表明光纤出射端面的光强分布应是介于高斯分布和几何分布之间的一种准高斯分布. 相似文献