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题名	固体激光非线性频率变换研究
作者	朱晓峥
学位类别	硕士
答辩日期	2003
授予单位	中国科学院上海光学精密机械研究所
导师	楼祺洪
关键词	固体激光 准相位匹配 受激拉曼散射 光纤激光
其他题名	Research of nonlinear frequency conversion used the solid-state laser
中文摘要	本论文主要是研究固体激光的非线性频率变换，具体内容包括固体激光的受激拉曼散射和利用准相位匹配技术对双包层光纤激光的倍频。固体激光和光纤激光具有光束质量好，易实现高功率的优点，而且其设备简单紧凑，对工作环境要求不高，因此具有广一泛的应用前景。为了扩大其应用范围刘其进行频率扩充是很有必要的。第一章综述了非线性光学频率变换技术及其原理，理论上介绍了具有普遍意义的非线性拙合波方程。对受激拉曼散射、角度相位匹配技术和准相位匹配技术进行了概述，并详细讨论了这三种非线咨胜频率变换的理论及其目前所采用的技术。第二章我们分别研究了利用固体倍频激光器三倍频和四倍频输出泵浦高压H_2拉曼池，获得了200nm～867nm波段范围内的17个波长的激光输出。我们知道影响受激拉曼散射的因素主要有；拉曼气体介质的压力、拉曼气体介质的类型、聚焦氏度、泵浦光功率和光束质量等。我们主要研究了拉曼介质压力对Stokes散射光的转换效率的影响，得到了各阶Stokes散射光能量最大时所对应的H_2压力。同时我们还研究了受激拉曼散射的脉冲压缩效应得到了3:l的脉宽压缩率，在H_2加入缓冲气体氦气可以提高二阶Stokes的拉曼散射闽值抑制一阶Stokes散射光能量向二阶转换，从而提高一阶Stokes散射光的转换效率。此外，我们还观察了受激拉曼散射中环行光斑的存在，证明了受激拉曼散射光中具有四波混频的成分。第三章我们在非线性棍合波稳态解的基础上推导了准相位匹配的揪合波方程组的一般解，山此推出倍频解。犷咋细讨论了倍频过程中的相位匹配因子△K_Q，△K_Q在倍频过程中有相当重要的作用，它决定转换效率的高低。然后基于相位失配理论对PPLN晶体的温度响应带宽和谱线响应带宽进行了理论推导，并给出了模拟解，和具体实验相比较，得到了比较好的吻合。第四章我们首先对双包层光纤激光器进行了介绍，给出了脉冲双包层光纤激光器的基木构成。利用该激光器对PPLN晶体进行了倍频研究，获得了59mw的绿色激光输出，转换效率达到6.1％。最高的转换效率出现泵浦功率650mw时，绿光输出功率为43.5mw，转换效率达到6.7％。在实验过程中我们还对PPLN品体的温度响应宽度和谱线响应宽度进行了研究，实验结果和第三章的理论计算基本一致。为了进行频谱分析，我们改进了传统的平而光栅摄谱仪，使其能实时的观测并实时的进行数据处理。
英文摘要	Nonlinear frequency conversion of solid-state laser has been studied in this article, which includes two parts, one is Stimulated Raman Scattering (SRS), and the other is second harmonic generation by double cladding fiber laser in PPLN. In the first chapter, based on Maxwell Equation, nonlinear coupling equation was deduced. Theory and experiments of nonlinear frequency conversion are reviewed. Technology of Stimulated Raman Scattering, angle phase matched (PM) and quasi-phase matched (QPM) are summarized and their theory was introduced in detail. In the second chapter, the Stimulated Raman Scattering (SRS) in H_2 pumped by the third harmonic (355nm) and the forth harmonic (266nm) of Nd:YAG laser are investigated respectively. 17 wavelengths of radiation are obtained in 200～867nm wavelength region. In our experiments the relationship between conversion efficiency of Stokes output and pressure of Raman medium (H_2) is studied, and pressure of H_2 that optimizes conversion efficiency of each order of Stokes are obtained. Moreover compressed pulse-width is observed, The maximum pulse-width compressed rate is up to 1/3. Adding buffer gas to Raman medium can improve the conversion efficiency of the first Stokes, and restrain the conversion efficiency of the second Stokes. In the third chapter, the quasi-phase-matching (QPM) theory for generate of second harmonic output is discussed. Based on the QPM second-order nonlinear coupling equation, the output power and conversion efficiency of frequency doubling are deduced with periodically structure PPLN. In which the factor of phase matched △K_Q is important to obtain high efficiency conversion. The bandwidth of pump laser beam to obtain frequency doubling in PPLN with different temperature is analyzed in detail. In the forth chapter, after introduced the double-clad fiber laser and the second harmonic generation in PPLN pumping by fiber laser are studied, 59mW average power green light is obtained with conversion efficiency is up to 6.1%. When the pump power is 650mW, the highest conversion efficiency is 6.7%. The relationship between green laser output and pumping laser bandwidth at different temperature of PPLN is investigated in detail.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16542]
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	朱晓峥. 固体激光非线性频率变换研究[D]. 中国科学院上海光学精密机械研究所. 2003.

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