全固体腔内和频拉曼黄光激光器理论与实验研究

发布时间：2018-04-24 23:33

本文选题：腔内和频 + 受激拉曼散射　；参考：《烟台大学》2016年硕士论文

【摘要】：受激拉曼散射(SRS)的发现,提供了一种生成不同频率的激光的输出方法,是一种非线性的方法。近年来对拉曼激光器的研究依然很受关注,尤其是在当前晶体生长技术的发展下,发现了许多性能优良的拉曼晶体,对受激拉曼散射的进一步研究提供了可能。对不同的泵浦光以及拉曼晶体的选择,使拉曼激光器产生一阶斯托克斯光的波长范围可以囊括从紫色波长到近红外波长。全固态拉曼激光器的研究如今已成为十分吸引研究者的前沿领域,其具有结构简单、组成紧凑、效率较高、不易受外界干扰的优点,在交通、通信、医学、测绘及国防等领域有极其重要的用途。560nm~600nm波段的黄绿光是多用途的一类激光,在藻红蛋白标记、生物免疫检测、医疗器械应用、生物化学科技等很多方面有着这重要的应用,其中560nm波段的激光已得到广泛应用。如何有效获得该段波长的激光一直是广大激光研究者的主要攻克方向,倍频(SHG)与和频(SFG)是两种获得黄绿光波段激光的有效途径。1120nm~1200nm波段的激光由激光材料来产生是特别困难的,使得560nm~600nm波段的激光由直接倍频来产生是很不容易的。因而拉曼光的产生显得就特别重要,其为倍频与和频产生黄绿光提供了可能。本论文首先介绍了相关全固体拉曼激光器的分类及研究现状和和频拉曼黄光激光器的研究情况,简单叙述了拉曼晶体及主要和频晶体。本论文以激光器速率方程为理论研究工具,分别推导出了被动调Q腔内和频拉曼激光器和主动调Q腔内和频拉曼激光器的速率方程,并分别进行了归一化处理,得到归一化的各个综合参数,然后运用常见晶体的参数,分别研究了各综合参数的恰当取值,并在适当取值下,进行了数值模拟,深入细致的研究了综合影响参量对输出激光脉冲的影响,模拟结果可以指导实验设计。基于理论研究,设计了二极管激光泵浦被动调Q拉曼激光器的实验。选用了当前常用的SrWO4拉曼活性介质,得到相应二极管激光泵浦被动调Q拉曼激光器的拉曼光输出。在输入泵浦激光功率4.12W时,得到的最大拉曼光输出功率达到了0.724W,拉曼转换的效率高达17.5%。这一实验结果非常好的反映了Sr WO4的优良拉曼特性。对影响拉曼光输出的各种激光器器件参数进行了研究,包括输入镜曲率半径、饱和吸收体初始透过率及输出镜对拉曼光的反射率等。本论文还就KTP晶体的和频性质进行了研究,设计出了被动调Q内腔式和频拉曼黄光激光器,并成功获得了黄绿光的输出,在输入泵浦功率4.12W时,获得的最大和频黄光输出达到0.109W,转换的效率为2.64%,脉宽为6.5ns。和频光的单脉冲能量为19.9?J,峰值功率为3.06kW。
[Abstract]:The discovery of stimulated Raman scattering (SRS) provides an output method for laser with different frequencies and is a nonlinear method. In recent years, the research of Raman laser is still concerned, especially with the development of crystal growth technology, many excellent Raman crystals have been found, which provides the possibility for the further study of stimulated Raman scattering (SRS). For different pump light and Raman crystal, the wavelength range of the first order Stokes laser can range from purple wavelength to near infrared wavelength. The research of all-solid-state Raman lasers has become a very attractive frontier for researchers. It has the advantages of simple structure, compact composition, high efficiency, and is not easily disturbed by the outside world, in traffic, communications, medicine, The yellowish green light, which has extremely important applications in the fields of mapping and national defense, is a kind of multipurpose laser. It has this important application in many fields, such as phycoerythrin labeling, bioimmunoassay, medical device application, biochemical science and technology, etc. Among them, 560nm laser has been widely used. How to effectively obtain the wavelength of the laser has been the main direction of laser researchers. SHG and SFG are two effective ways to obtain the yellowish-green wavelength laser. It is very difficult for the laser at 1200nm wavelength to be produced by the laser material. It is not easy to make 560nm~600nm laser generated by direct frequency doubling. Therefore, the generation of Raman light is particularly important, which makes it possible to produce yellowish green light by double frequency and sum frequency. In this paper, the classification and research status of all solid state Raman lasers and the current situation of yellow Raman lasers are introduced, and the Raman crystals and main sum-frequency crystals are briefly described. In this paper, the rate equations of passively Q-switched intracavity sum-frequency Raman lasers and active Q-switched intracavity sum-frequency Raman lasers are derived and normalized respectively. The normalized comprehensive parameters are obtained, and then the proper values of each synthetic parameter are studied by using the common crystal parameters. The numerical simulation is carried out under the appropriate values. The influence of the synthetic influence parameters on the output laser pulse is studied in detail. The simulation results can guide the experimental design. Based on the theoretical research, the experiment of passively Q-switched Raman laser pumped by diode laser is designed. The passively Q-switched Raman laser pumped by the corresponding diode laser has been obtained by using the current active SrWO4 Raman medium. At the input pump power of 4.12 W, the maximum Raman output power is 0.724 W, and the Raman conversion efficiency is as high as 17.5 W. The experimental results well reflect the excellent Raman characteristics of Sr WO4. The laser device parameters which affect the Raman output are studied, including the curvature radius of the input mirror, the initial transmittance of the saturated absorber and the reflectivity of the output mirror to the Raman light. The sum-frequency properties of KTP crystal are also studied in this paper. A passive Q-switched intracavity sum-frequency Raman yellow laser is designed, and the output of yellowish green light is obtained successfully. The output power is 4.12W at the input pump power. The maximum sum frequency yellow light output is 0.109 W, the conversion efficiency is 2.64 and the pulse width is 6.5 ns. The single pulse energy of sum-frequency light is 19.9kW and the peak power is 3.06kW.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN248

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