高功率Tm:YAP连续激光器的研究

发布时间：2018-03-10 02:00

本文选题：2μm激光器　切入点：Tm:YAP　出处：《北京交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：2μm波段激光器经过长期发展,已经进入科研、军事、激光医疗、环境保护、材料加工等领域,并且得到了广泛的应用。由于2μm激光在许多方面所具有的优越性质,2μm激光器已经成为固体激光器中一个重要的研究领域。鉴于其重要的应用价值,本文对Tm:YAP激光器展开了理论分析和实验研究,具体工作包括以下五个方面： (1)对Tm:YAP晶体特性的分析,包括Tm3+离子的能级结构特性分析,YAP晶体的物理特性分析,Tm:YAP晶体的光谱特性分析,以及Tm:YAP晶体的热透镜效应四个方面。其中,主要研究了Tm:YAP晶体的热透镜效应,包括Tm:YAP晶体的热透镜焦距的理论推导和结合具体参数的数值计算。 (2)研究了Tm:YAP激光器的速率方程模型,包括：Tm:YAP激光器低四位能级速率方程模型和连续Tm:YAP激光器速率方程模型。研究激光器的发光机理是研究激光器的基础,而速率方程则是研究激光器工作过程的主要依据,通过研究模型并求解速率方程,分析各个因素对激光器输出的影响,这也是优化设计激光器的基础。 (3)分析了直腔的理论模型,利用MATLAB软件对谐振腔进行优化设计,模拟出激光器的稳区范围和激光光斑半径在腔内的变化情况。结合实验,对比各种腔型的输出功率情况,选择有效补偿Tm:YAP晶体热效应的最佳腔型,实现连续Tm:YAP激光器的稳定、高功率输出。当输出透镜透过率为5%时,获得4.92W的1.98μm连续波激光输出,相对应的泵浦功率为17W,斜率效率为36.57%。使用ANDOR光谱仪测得激光器输出中心波长为1985nm。采用NanoScan光束测量仪,测得了在同一位置不同泵浦功率下的输出光斑轮廓。 (4)研究了Z型腔Tm:YAP激光器的理论模型,设计了四镜折叠腔,根据四镜折叠腔的稳定性条件和像散补偿条件,利用MATLAB软件对谐振腔进行优化设计。结合实验,对比不同腔型的功率输出情况,选出最佳腔型。输入泵浦功率为14W时,得到最大输出功率为2.27W,斜率效率为23.9%。 (5)对可调谐Tm:YAP激光器进行了理论设计研究,主要包括双折射滤光片的设计和工作原理分析。分析了在腔内加双折射滤光片和布氏板实现Tm:YAP激光器调谐运转的基本理论。
[Abstract]:After a long period of development, 2 渭 m band lasers have entered the fields of scientific research, military, laser medical treatment, environmental protection, material processing, etc. Because of its advantages in many aspects, 2 渭 m laser has become an important research field in solid-state lasers. In this paper, the theoretical analysis and experimental study of Tm:YAP laser are carried out. The specific work includes the following five aspects:. 1) the analysis of Tm:YAP crystal characteristics, including the analysis of the energy level structure of Tm3 ion and the analysis of the spectral characteristics of Tm:YAP crystal and the thermal lens effect of Tm:YAP crystal. The thermal lens effect of Tm:YAP crystal is studied, including the theoretical derivation of the focal length of thermal lens of Tm:YAP crystal and the numerical calculation combined with specific parameters. (2) the rate equation model of Tm:YAP laser is studied, including the model of low four-bit energy level rate equation and the rate equation model of CW Tm:YAP laser. The study of the luminescence mechanism of the laser is the basis of the study of the laser. The rate equation is the main basis for studying the working process of the laser. By studying the model and solving the rate equation, the influence of various factors on the laser output is analyzed, which is also the basis of the optimal design of the laser. The theoretical model of the straight cavity is analyzed, and the optimal design of the resonator is carried out by using MATLAB software. The stable range of the laser and the variation of the laser spot radius in the cavity are simulated. In combination with the experiment, the output power of various cavity types is compared. The optimal cavity for effectively compensating the thermal effect of Tm:YAP crystal is chosen to realize the stable and high power output of the CW Tm:YAP laser. When the transmission rate of the output lens is 5, the 1.98 渭 m CW laser output of 4.92 W is obtained. The pump power is 17W and the slope efficiency is 36.57.The output center wavelength of the laser is measured by ANDOR spectrometer to be 1985nm.The profile of the output spot at the same position and different pump power is measured by using the NanoScan beam measuring instrument. The theoretical model of Z-cavity Tm:YAP laser is studied, and the four-mirror folded cavity is designed. According to the stability condition and astigmatic compensation condition of four-mirror folded cavity, the resonator is optimized by MATLAB software. When the input pump power is 14W, the maximum output power is 2.27W and the slope efficiency is 23.9W. In this paper, the theoretical design of tunable Tm:YAP laser is studied, including the design of birefringent filter and the analysis of its working principle. The basic theory of tunable operation of Tm:YAP laser by adding birefringent filter and Brinell plate into cavity is analyzed.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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