【作者】 刘军；

【导师】 陈慰宗； 魏晓峰；

【作者基本信息】 西北大学 ， 光学， 2003， 硕士

【摘要】 由于超短超强脉冲激光在x射线激光、惯性约束核聚变、实验天体物理、激光粒子加速器等强场物理研究领域内的重要应用，超短脉冲激光放大技术目前已成为超短脉冲激光技术研究的热点之一。它包括啁啾脉冲放大(CPA)和光参量啁啾脉冲放大(OPCPA)两大类。由于钛宝石晶体的优良性能，以钛宝石为增益介质的啁啾脉冲激光放大技术飞速发展，世界各科技大国相继建成了百太瓦级的钛宝石超短超强脉冲激光装置。而新兴的光参量啁啾脉冲放大因为其众多的优点而引起了人们极大的研究兴趣。 本文实验研究是指作者在激光聚变中心参与的20TW全钛宝石飞秒超短脉冲激光装置的工程建设工作的理论与实验研究总结，对此系统的振荡器、再生放大器、多程放大器、展宽器与压缩器及同步系统进行了较为系统的分析。理论部分主要是对新兴的光参量啁啾脉冲放大技术的相位匹配、参量范围、时空走离、增益及带宽特性等基础理论进行了分析，并对常用的BBO、LBO和KDP基础特性进行了比较分析，这对于光参量啁啾脉冲放大系统的设计具有一定的实际意义。我们还在考虑时间波形和相位失配的情况下，利用四阶龙格-库塔法对光参量啁啾脉冲放大进行了数值模拟计算，得到了不同泵浦光时间波形时的增益与频谱特性。在泵浦光为高斯时间波形且脉宽与信号光差不多时，出现增益窄化；而当泵浦光近似为时间平顶时，饱和放大后光谱增宽。更多还原

【Abstract】 Ultrashort pulse amplification, including chirped pulse amplification (CPA) and optical parametric chirped pulse amplification (OPCPA), has been becoming one of the hot researches in the field of ultrashort pulse laser technology because ultrashort and ultrahigh intensity pulse laser has important applications in high field physics, such as X-ray laser, ICF, laboratory astrophysics, laser particle accelerator, and so on. Since Ti:sappire owns many great properties, chirped pulse amplification based on Ti:sappire makes rapid technical progress and many developed countries have built up 100TW-grade Ti:sappire ultrashort and ultrahigh pulse laser system. Optical parametric chirped pulse amplification gets great academic interests because of its many merits.In this paper, the experimental part is the sum-up of theoretical and experimental studies on a 20TW Ti:sappire femtoscecond high-intensity laser system while author worked in the Research Center of Laser Fusion of CAEP, which includes oscillator, regenerative amplifier, multi-pass amplifier, stretcher, compressor and synchronization system. The theoretical part mainly refers to studies of optical parametric chirped pulse amplification. We analyze some basic theories of OPCPA, such as phase matching, parametric bandwidth, walk-off in space and time, gain property and so on, and compare the basic properties of BBO, LBO and KDP. We also use fourth Runge-Kutta method simulate the OPCPA process in the case of considering signal and pump temporal profile and phase mismatching and get gain and spectra properties at different pump temporal profile. The results show that there is gain narrowing when pump is Gaussian temporal profile and it’s pulse width close to signal’s and that the spectrum extended in the case of saturated amplification when pump is near top-hat temporal profile.更多还原