光参量啁啾脉冲放大数值模拟平台中超短脉冲聚焦模拟算法  

Ultra-short pulse focusing algorithm for optical parametric chirp pulse amplification numerical simulation platform

作　　者：陈经纬 罗斌[1] 曾小明[2] 母杰[2] 王逍[2] Chen Jing-Wei;Luo Bin;Zeng Xiao-Ming;Mu Jie;Wang Xiao(The School of Information&Technology,Southwest of Jiaotong University,Chengdu 611756,China;Research Center of Laser Fusion,China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]西南交通大学信息科学与技术学院,成都611756 [2]中国工程物理研究院激光聚变研究中心,绵阳621900

出　　处：《物理学报》2023年第9期225-233,共9页Acta Physica Sinica

基　　金：等离子体物理重点实验室(批准号:22-ZDJJ-06-03)资助的课题。

摘　　要：光参量啁啾脉冲放大(OPCPA)数值模拟平台研发涉及到光脉冲的展宽压缩、参量放大和聚焦输出等物理模型,针对其中的超短脉冲聚焦算法,本文推导给出了输出光场范围可调、并具备快速傅里叶算法的数学表达式,解决了传统菲涅尔远场衍射聚焦算法面临如何提高光场分辨率和保持各波长分量计算网格大小一致的难题,为后续直接进行时频逆变换、高效分析超短脉冲聚焦后的时空耦合特性提供了便利.数值仿真结果揭示出,超短脉冲聚焦场暗环区域表现出强烈的时空耦合特征.本算法已成功应用于OPCPA数值仿真平台研发中,可望在超短激光脉冲装置的优化设计工作中发挥重要作用.The development of optical parametric chirp pulse amplification(OPCPA)numerical simulation platform involves physical models such as broadening and compression of optical pulse,parametric amplification and focusing output.In the simulation platform,the Fresnel far-field diffraction equation is usually used to simulate the characteristics of ultrashort pulse focusing.Firstly,we need to calculate the optical field distribution of different wavelength components in the ultrashort pulse,and then use the inverse Fourier transform to obtain the temporal and spatial distribution characteristics of the pulse.However,for different wavelength components,the sizes of focused field grids obtained by the far-field algorithm are not equal,and subsequent resampling is required,which will increase the amount of calculation.In addition,due to the limitation of the calculation range of the light field in the pulse broadening and compression,there is also a problem of poor resolution of the focused field.In this work,the mathematical expression that can adjust the range of the output light field and use the fast fourier algorithm is derived.The main mechanism of this algorithm is as follows.Based on the Fresnel far-field diffraction equation,the output field is sampled independently in the discrete calculation process to meet the requirements for adjustable range of the output field.After identity transformation,the output field results can be calculated by the fast Fourier algorithm.Furthermore,the sampling conditions that need to be satisfied when using the algorithm are further analyzed and discussed.It solves the problem of how to improve the resolution of light field and keep the computational grid size of each wavelength component consistent when the traditional Fresnel far field diffraction is used to simulate the focusing process,which provides the convenience for the subsequent direct time-frequency inverse transformation.The numerical simulation results reveal that the dark ring region of the ultrashort pulse focusing fie

关 键 词：超短脉冲 聚焦算法 时空分布 快速傅里叶变换 

分 类 号：TN24[电子电信—物理电子学]