LD侧面泵浦全固态多波长激光器的研究

【作者】 陈秀艳；

【导师】 白晋涛；

【作者基本信息】 西北大学 ， 光学， 2009， 博士

【摘要】 全固态多波长激光器自身所具有的多波长激光同时或交替输出的独特优势,使其应用范围比单一波长激光装置更加广泛,尤其在医学领域中,从现代临床医学发展的趋势看,全固态多波长激光器有着不可替代的作用,因其具有体积小、效率高、节能环保、寿命长等一系列优点,已有逐步取代多波长气体和染料激光器的趋势,潜在的市场需求也十分巨大。本文以“LD侧面泵浦全固态多波长激光同时输出”为研究中心,对不同波长频率变换理论、多波长声光调Q理论进行了理论研究,对连续和准连续红(660nm)、黄(589nm)、绿(532nm)三波长激光进行了系统的腔型设计和实验研究,对1064nm、1319nm基波及其二次谐波同时输出特性进行了初步实验研究,并对高功率泵浦条件下其热透镜效应的补偿进行了理论计算和模拟。论文工作的主要成果如下:1.概述了获得多波长激光的方法、全固态多波长激光晶体及器件的研究现状、全固态多波长激光在医学上的应用以及本论文研究的主要内容、目的和意义;2.从耦合波方程出发,推导了平面波和高斯波近似下小信号和大信号和频转换效率与倍频转换效率,计算模拟了不同相位匹配条件下相位匹配角度之间的关系以及和频晶体温度变化对相位匹配角度的影响,计算模拟了不同相位匹配条件下的有效非线性系数以及和频晶体温度对有效非线性系数的影响;3.从速率方程出发,建立了多波长激光声光调Q的速率方程,研究了声光调Q技术对多波长激光输出特性的影响,包括对同一激光晶体同时发出不同波长基频激光经非线性频率变换实现多波长激光输出的影响,以及不同激光晶体发出不同波长基频光后经非线性频率变换实现多波长激光输出的影响;4.研究了红(660nm)、黄(589nm)、绿(532nm)三波长激光连续输出和准连续输出的特性,首先从全固态黄光激光器的研究现状出发设计了新型的“T”型复合腔黄光激光系统,并对激光腔中各参数对系统性能的影响作了分析,在此基础上,发展出“十”字复合腔结构,在实验中获得了高功率、高光束质量、稳定性能好的红、黄、绿多波长激光输出;5.主要研究了红(660nm)、绿(532nm)及红外(1064nm和1319nm)多波长激光输出的特性,从理论上分析了不同波长激光腔镜透过率、腔内损耗以及水温等对多波长激光输出特性的影响,在实验中分别采用不同型号的模块实现多波长激光输出,对理论进行验证,并在在理论上初步设计分析了高功率下望远镜系统对热透镜效应的补偿。更多还原

【Abstract】 All-solid-state multi-wavelength lasers have wide scope of applications in many fields than single wavelength lasers, because it is of the unique advantages of multi-wavelength lasers emission simultaneously or alternatively. With the development of modern clinical medicine, all-solid-state multi-wavelength laser has irreplaceable role, and it will gradually replace multi-wavelength gas and dye laser because of its small size, high efficiency, high energy and environmental protection, long lifetime, etc., so the potential market demand is quite large. This paper focused on the study of "LD side-pumped multi-wavelength all-solid-state lasers output simultaneously" , then made theoretical research on frequency conversion of different-wavelength lasrs and multi-wavelength acousto-optic Q. On the basis of designing the optimal cavity, the experimental research on the continuous and quasi-continuous three-wavelength lasers (red, yellow and green) has been done. The preliminary experimental research about simultaneous output of fundamental and second harmonic wave has also been studied, then the theoretical calculation and simulation about compensation of the thermal lens in the condition of high-power has been researched as well. The main contents of the paper are listed as follows:1. Reviewed the methods of obtaining multi-wavelength lasers, the research status of all-solid-state multi-wavelength laser crystals and devices, the application of multi-wavelength lasers in medicine, and generalized the main content, purpose and significance of this paper.2. Based on the coupled-wave equation, the sum and double frequency conversion efficiency of small and large signals in the approximation of plane wave and Gaussian wave were derived. The relationship of phase-matching angles in different phase-matching conditions and the impact of the temperature of sum frequency crystal on phase-matching angle were also calculated and simulated. After that, the impact of phase-matching conditions and temperature changes in sum frequency crystal on effective nonlinear coefficient were calculated and simulated as well.3. Based on the rate equation, the multi-wavelength acousto-optic Q-rate equation was established, the impact of acousto-optic Q-technology on the multi-wavelength laser output characteristics has also been studied, including the different wavelengths emitted simultaneously from one crystal and emitted from different crystals. 4. The continuous and quasi-continuous output characteristics of red (660nm), yellow (589nm), and green (532nm) laser were researched. A new "T" type of yellow composite cavity laser systems was designed, and the impact of laser cavity parameters on the system performance was also analyzed. On this basis, a cruciform structure composite cavity was developed, and a red, yellow and green multi-wavelength laser output with high-power, high beam quality and stable performance was realized .5. The red (660nm), green (532nm) and infrared (1064nm and 1319nm) multi-wavelength lasers output characteristics were mainly studied. The impact of different cavity mirror transmittance and the intra-cavity loss of different wavelengths on the multi-wavelength laser output characteristics were analyzed theoretically. Different types of modules were used to obtain multi-wavelength laser output in the experiment to , and the compensation of the thermal lens effect by the telescope system in the condition of high-power was analyzed theoretically as well.更多还原