Ld pumped laser featuring with high - efficiency , sound quality , long lifetime , miniaturization , sound reliability and leading laser full - solidified , attracted great attentions from academic circles , industry field and military field . therefore , it is of great importance to develop new laser crystal Ld泵浦晶体激光器的高效率、高质量、长寿命、小型化、高可靠性以及实现激光器全固化等优越性，引起了学术界、产业界和军方的高度重视，因而探索新型激光晶体的工作显得非常重要。
The analyses given in this paper to quasi - three - level for 946 nm laser are complete . the relation between 946 nm laser transmission and optimal crystal length has been derived from the rate equations describing the population inversion and the photon density in the laser cavity in the steady - state case . the minimal claims to coating have been given on the base of contrasting 946 nm transmission with 1064 nm transmission in the condition of different cavity losses and how the pump beam radius in the laser crystal and optimal crystal length affect the laser threshold and output power of 946 nm laser has been given as well 对产生946nm谱线的准三能级结构给出了较为完整的分析，利用激光谐振腔处于稳态时的速率方程，导出了准三能级nd ： yag946nm起振时，透射损耗与最佳激光晶体长度的关系，在与1064nm透射损耗相比较的基础上，给出了不同的腔损耗情况下的最低镀膜要求，并且给出了激光阈值、输出功率和最佳激光晶体长度及泵光光斑大小的关系，这为设计室温下高效运转的946nm激光器的提供了理论基础，这种分析方法对研究此类低增益，准三能级或三能级激光系统输出特性有借鉴意义。
Abstract : in view of the crystal structure , this paper repo rts thecharacter of single crystal growth of germanate and the properties as me dium of laser crystal . the study and progress in germanate crystals used as widel y tunable laser crystal , self - doubling - frequency crystal and highly efficient and low pumping threshold laser crystal are introduced 文摘:从晶体结构上分析了锗酸盐的单晶生长和作为激光晶体基质的特点，并介绍了锗酸盐作为可调谐激光晶体，自倍频晶体，高转换效率和低泵浦阈值的激光晶体的研究及进展。
The classification and characterization of the laser crystals were introduced in the thesis , and the research and development of the yvo4 crystal were systematically reviewed . the detailed experimental project was carried out to probe the reason of the absorption peak in the 1552nm of yvo4 crystal . the raw materials of yvo4 were synthesized through several different procedures 本文简要的介绍了激光晶体的分类及其性能，对钒酸钇晶体的现状和发展进行了总结，并针对本课题的目的设计了详尽的实验方案以探究部分钒酸钇晶体在1552nm处存在吸收峰的原因。
In the second chapter , the operating principle of solid - state laser is analyzed . based on the model of four - level system , the interacting theory between laser field and laser crystal is studied by the rate equation theory , then the characters , such as threshold power , output power , slope efficiency etc . , of solid - state laser are deduced 第二章分析了固体激光器的工作原理，以四能级系统为模型，应用速率方程理论研究了激光场与激光晶体之间相互作用理论，导出了固体激光器的阈值功率、输出功率和斜效率等特性。
The history , development and present conditions of diode pumped solid state lasers are reviewed , some laser crystals in common use are introduced and some import parameters of theirs are given . the q - switched technology is summarized from all round , and the major researches we have made and the present conditions about overseas and domestic of our country are summarized as well 回顾了半导体激光器( ld )泵浦固体激光器的发展历史和现状；介绍了几种目前常用的激光增益介质，并给出一些激光特性参数；对调q技术作比较全面的介绍；总结目前国内外的研究现状和本论文研究的主要内容。
The keys for laser crystal to grow in the same diameter are the diameter - measure system and control arithmetic , when crystal grow , the temperature is up to thousands of centigrade , and general diameter measure methods ca n ' t gain high precision , which will depress the total control effects 在激光晶体生长等径控制过程中，有两个关键环节：测径数据采集系统和控制算法。晶体生长是在数千度的高温下进行的，采用常规的测径方法，精度不高，这将对整个系统的控制性能产生影响。
Based on the rate - equation theory of four - level system , the expressions of threshold pump power , output power and slope efficiency are given . the influence of space distribution of pump light ( the position of focusing point , dimension of pumping light and divergence angle ) to the output characteristics are also discussed . then , by investigating the effects of thermal effect of laser crystal on the size of laser cavity mode , we obtain the mode - matching principle of high power laser diode end - pumped solid - state lasers 其中，在泵浦光的空间分布变量中我们分别考虑了泵浦光聚焦后的腰斑大小、聚焦腰斑在增益介质中的位置以及泵浦光在介质中发散角的影响；然后我们研究了在高泵浦功率下激光晶体因吸收泵浦光而产生的热效应所导致的热透镜效应以及热致衍射损耗，通过分析它们对振荡激光腔模尺寸的影响，得到了高功率半导体激光二极管端面泵浦固体激光器模式匹配的要求，为高功率连续单频nd ： yvo _ 4激光器的优化设计提供了理论依据。
So , today , they are widely used in fields of photoelectrics industry , military , medical treatment , scientific research , and etc . nd : gdvo4 is a new laser crystal which is reported in 1992 for the first time . it will be a good replacement of nd : yvo4 and nd : yag because of its high emission cross section and thermal conductivity Nd : gdvo _ 4是1992年出现的一种新型激光晶体，发射截面和吸收截面都较大，而且热导率高，是nd : yvo _ 4和nd : yag的良好替代品，是一种非常适合ld端面泵浦的激光增益介质。
Some researches about frequency doubling are made , and two methods to improve intensity of second frequency generation are given . we realized q - switched 532 nm laser , by using nd : gdvo4 as laser crystal , using cr4 + : yag as saturable absorber , using ktp as intra - cavity frequency doubling crystal . average power of 109mw , repetition of 40khz , pulse width of 30ns , pulse energy of 2 . 6uj , peak power of 91w are obtained 4 .对倍频理论进行研究和分析:讨论两种提高二次谐波功率密度的方一法;实验匕在国内首次实现ld端面泵浦nd : gdvo4 / ktp ，用cr4 + : yag作为可饱和吸收片的绿光激光器，腔内倍频得到了平均功率为109mw 、重复频率为40khz 、脉宽为3ons 、单脉冲能量为2 . 6闪、峰值功率为glw的调q绿光输出。
