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题名	超短脉冲激光放大系统的宽带放大及脉冲整形的若干技术研究
作者	姜永亮
学位类别	博士
答辩日期	2007
授予单位	中国科学院上海光学精密机械研究所
导师	徐至展
关键词	光学参量啁啾脉冲放大 准相位匹配 啁啾脉冲放大 主动脉冲整形 光子晶体光纤
其他题名	Research on some techniques for broadband amplification and pulse shaping in ultra-short pulse laser system
中文摘要	超短激光脉冲已在光频测量、超快过程研究、惯性约束聚变新途径等科学技术前沿领域得到了广泛的应用。目前，超短激光脉冲的放大主要有啁啾脉冲放大 (Chirped Pulse Amplification，CPA)和光学参量啁啾脉冲放大(Optical Parametric Chirped Pulse Amplification，OPCPA)两种方式，其中CPA技术目前应用范围最广，而OPCPA技术则具有更强劲的发展潜力。本论文重点研究了基于新晶体、新相位匹配方式的宽带OPCPA及其新波段宽带种子源中的若干关键技术问题，还研究了超短脉冲激光放大系统的主动脉冲整形技术。本论文的主要结论和创新点概括如下： 1．针对非线性放大过程中转换效率和稳定性等问题进行了理论分析，提出利用近共线近简并饱和放大实现宽带高效率稳定OPCPA的方案，在实验中利用多级LBO晶体得到了光谱半高全宽37 nm、增益超过1.9×108的宽带高增益放大，转换效率达到了32.9%，在泵浦脉冲能量起伏为10%的条件下获得了能量起伏为7.8%的稳定输出。 2．对基于新型周期极化晶体的近共线近简并准相位匹配(Quasi-Phase Matched，QPM)OPCPA进行了理论分析，并利用0.5mm厚的PPLT晶体实现了宽带近共线近简并0类准相位匹配的OPCPA，在较低泵浦能量(600µJ)下获得了高达1.7×106的单程增益和较宽的增益带宽，泵浦光的总转换效率达到了10.3%。 3．采用基于可编程声光色散滤波器(Acousto-Optic Programmable Dispersion Filter，AOPDF)的主动脉冲整形技术对SPITFIRE激光系统中的增益窄化效应和高阶未补偿色散进行了优化，将输出脉冲宽度从原来的51fs压缩到30fs，得到了接近傅里叶变换极限(28fs)的高质量脉冲输出，并在成丝压缩实验中获得了12fs的压缩脉冲输出；将AOPDF应用到其他激光系统上也得到了较好的优化效果；分析了CPA激光系统中增益窄化及色散等因素对输出脉冲质量的影响，并探讨了基于AOPDF的主动脉冲整形技术在OPCPA系统中的应用。 4．对基于光子晶体光纤(Photonic Crystal Fiber，PCF)的新波段可调谐宽带OPCPA种子源进行研究。建立了超短脉冲在PCF中的演化模型，理论模拟并实验研究了保偏高非线性PCF中不同条件下输出超连续谱的变化规律；结合主动脉冲整形技术研究了入射脉冲初始啁啾对输出超连续谱性质的影响，发现在入射脉冲能量不变的情况下引入一定的正啁啾能有效地增强超连续谱转换效率，且存在一个最佳的正啁啾值使得转换效率达到最大值；分析了PCF在OPCPA系统中的应用方案，首次提出了用PCF代替空心光纤获得1500nm波段可调谐载波包络相位(Carrier Envelope Phase，CEP)稳定的种子脉冲的技术路线。
英文摘要	Ultra-short pulse laser has been used widely in many frontier fields, such as ultrafast physical-chemical processes, optical frequency metrology, and the new approach to inertial confinement fusion. Ultra-short pulses can be amplified by two methods: Chirped Pulse Amplification (CPA) and Optical Parametric Chirped Pulse Amplification (OPCPA). The CPA technique is widely employed and the OPCPA technique has been proved to be more potential. This dissertation is focused on some key techniques in broadband OPCPA with novel crystal and new phase-matching condition, and in new broadband seed sources. The active pulse shaping technique in ultra-short laser amplification system also has been researched in this dissertation. The main results achieved in this dissertation have been summarized as following: 1. Based on the theorectical analyse on the conversion efficiency and stability in nonlinear amplification process, a new scheme is proposed to obtain high efficient stable broadband OPCPA with near-collinear near-degenerated saturated amplification. Output pusles with the spectral width (FWHM) of 37nm have been achieved with multi-LBO crystals, and the gain is 1.9×108. The total conversion efficiency is 32.9%, and the energy fluctuation of the output pulse is 7.8% when the fluctuation of the pump pulse is 10%. 2. The near-collinear and near-degenerated quasi-phase matched (QPM) OPCPA based on a new type of periodic polarized crystal has been theoretically analyzed. Using a 0.5mm thick PPLT crystal, a near-collinear and near-degenerated Type-0 QPM broadband OPCPA has been demonstrated. A single pass gain of 1.7×106 is obtained with low pump energy of 600µJ, and the pump conversion efficiency is 10.3%. 3. Using the active pulse shaping techenique based on an acoustic optical programmable dispersion filter (AOPDF), the pulse width of the SPITFIRE system has been compressed from 51fs to 30fs, which is near the Fourier transform limitation (28fs), and compressed 12 fs pulses are output from the extracavity pulse compression experiment. Good results have been achieved using an AOPDF in other systems; The effects of gain narrowing and dispersion in CPA laser system have been analyzed, and the application of active pulse shaping technique in OPCPA has been discussed. 4. The new band tunable seed source based on photonic crystal fiber (PCF) is studied, which could be used as OPCPA signal. The numerical model of ultra-short pulse propagation in PCF has been set up; The supercontinuum generation processes in high nonlinear PCF under different conditions have been theoretically and experimentally studied; Based on the active pulse shaping technology the effects of initial chirp have been investigated; With the same pump energy, the supercontinuum generation can be enhanced by positive initial chirp and an optimal positive chirp was found to achieve the largest conversion efficiency; An OPCPA scheme using PCF instead of hollow fiber to achieve 1500nm band tunable carrier envelope phase (CEP) stabilized seed pulse is first proposed.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15561]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	姜永亮. 超短脉冲激光放大系统的宽带放大及脉冲整形的若干技术研究[D]. 中国科学院上海光学精密机械研究所. 2007.

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