532nm脉冲泵浦的近红外可调谐光参量振荡技术研究

发布时间：2018-05-16 03:06

本文选题：非线性光学 + 光参量振荡　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：光参量振荡技术(OPO)是激光频率转换技术中重要的组成部分,具有频率覆盖范围广,能量转换效率高的特点,可以灵活地与多种激光器组合形成性能迥异的激光系统,其中利用OPO的频率转换特性产生高功率的可调谐脉冲光源在光谱检测中具有重要应用。Nd:YAG主(被)动调Q激光器是典型的高功率脉冲输出系统,广泛应用于各种场合,将其倍频后产生的532 nm脉冲是常见的可调谐激光泵浦源,将OPO波长转换技术与Nd:YAG倍频激光器结合产生近红外波段的可调谐脉冲输出是本文的研究目的。本文研究的主要内容如下:1、介绍了非线性过程和晶体物理的相关理论,利用晶体的Sellmeier色散方程计算了常见晶体BBO、LBO、Bi BO以及KTP将532 nm光转换为800 nm光的临界相位匹配角及其对应的有效非线性系数,最终选择LBO晶体在XY平面的I类相位匹配作为OPO输出系统的非线性转换晶体;2、模拟计算了OPO的泵浦光参数和腔参数对OPO输出阈值和效率的影响,给出了提高OPO信号能量转换效率的优化方法,实验研究了泵浦增强OPO和无泵浦增强OPO两种输出方式,通过对谐振腔镜反射率的优化组合,最终在泵浦增强OPO中获得了高达30%的信号光能量转换效率;3、根据晶体的热光色散方程计算了温度对OPO输出中心波长和增益谱宽的影响,给出了OPO温控系统的参数要求,最终利用温度调谐获得了760 nm-790nm的近红外波段输出,并分析了晶体与泵浦光间角度误差对OPO温度调谐范围的影响。
[Abstract]:Optical parametric oscillation (OPO) is an important part of laser frequency conversion technology. It has the characteristics of wide frequency coverage and high energy conversion efficiency. The high power tunable pulse source generated by the frequency conversion characteristic of OPO has important applications in spectral detection. ND: YAG main Q-switched laser is a typical high-power pulse output system, which is widely used in various situations. The 532nm pulse is a common tunable laser pump source. The tunable pulse output in near infrared band is generated by combining the OPO wavelength conversion technique with the Nd:YAG frequency-doubling laser. The main contents of this paper are as follows: 1. The related theories of nonlinear process and crystal physics are introduced. Using the Sellmeier dispersion equation of the crystal, the critical phase matching angle and the corresponding effective nonlinear coefficient of the common crystal BBO-LBO-Bi BO and KTP for converting 532nm light to 800nm light are calculated. Finally, the class I phase matching of LBO crystal in XY plane is chosen as the nonlinear conversion crystal of OPO output system. The effects of pump light parameters and cavity parameters of OPO on the output threshold and efficiency of OPO are simulated and calculated. An optimized method to improve the energy conversion efficiency of OPO signal is presented. Two output modes, pump enhanced OPO and unpumped enhanced OPO, are experimentally studied. The optimum combination of the reflectivity of resonant mirrors is obtained. Finally, 30% of the signal energy conversion efficiency is obtained in pumped enhanced OPO. According to the thermo-optical dispersion equation of the crystal, the influence of temperature on the wavelength and gain spectrum width of the output center of OPO is calculated, and the parameter requirements of the OPO temperature control system are given. Finally, the near infrared band output of 760 nm-790nm is obtained by temperature tuning, and the influence of angle error between crystal and pump light on the tuning range of OPO temperature is analyzed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN24

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