Frequency-conversion modeling with spatially and temporally varying beams
Frequency-conversion modeling with spatially and temporally varying beams
复制标题
DOI：
10.1117/12.228256
复制
发表时间：
1995-12
期刊：
影响因子：
--
通讯作者：
P. Milonni;J. Auerbach;D. Eimerl
中科院分区：
文献类型：
--
作者：
P. Milonni;J. Auerbach;D. Eimerl
本文建立了一个计算钕玻璃激光辐射在KDP中三次谐波转换的模型，包括傍轴衍射、走离、任意时间依赖性和B积分效应。该码是四维的，因为它包括沿着和横向于传播方向的空间场变化以及时间变化。采用基于快速傅立叶变换和龙格-库塔积分器的分步算法在空间和时间上进行前向推进。该代码已被基准对简化代码的结果在平面波或单色限制，转换效率的预测是在利弗莫尔的实验结果很好的协议。输入波前的空间相位波纹和时间带宽在三倍频晶体中比在倍频晶体中重要得多。双倍器设计允许在宽强度范围内实现高三倍效率，而具有高转换效率的大带宽可以通过两个三倍器实现。
A computer model of third-harmonic conversion of Nd:glass laser radiation in KDP, including paraxial diffraction, walkoff, arbitrary temporal dependence, and B-integral effects, has been developed. The code is four-dimensional in that it includes the spatial field variations along and transverse to the propagation direction as well as temporal variations. A split-step algorithm based on the fast Fourier transform and a Runge-Kutta integrator is employed for forward stepping in space and time. The code has been benchmarked against results of simplified codes in the plane-wave or monochromatic limits, and predictions for conversion efficiencies are in good agreement with experimental results at Livermore. Spatial phase ripples and temporal bandwidth of the input wavefront are much more important in the tripling crystal(s) than in the doubler(s). Two-doubler designs allow for high tripling efficiencies over a broad range of intensities, while large bandwidths with high conversion efficiencies can be realized with two triplers.