【作者】 裴静静；

【导师】 宋博；

【作者基本信息】 长春理工大学 ， 材料物理与化学， 2010， 硕士

【摘要】 准相位匹配概念的提出已有半个多世纪,但在实际应用方面,尤其是产品的商业化方面没有很大的进展,这主要受限于准相位匹配材料。过去人们制取这种结构的材料主要集中在同成份的钽酸锂、同成份的铌酸锂(CLN)、磷酸氧钛钾(KTP)等材料上,但这些材料存在的主要问题就是矫顽场比较高,且光损伤阈值比较低。这几年主要的工作集中在改进这些材料本身的缺点上,例如生长近化学计量比的钽酸锂(SLT)和铌酸锂(SLN)就是改进材料性能的主要方面,晶体损伤阈值提高了1-2个数量级,矫顽场下降了1个数量级。本课题采用铌酸锂(LN)为基质材料,以一种比较简单实用的方法,来生长成本比较低的同成分掺镁铌酸锂晶体,并制作准相位匹配器件。本实验在适宜的温度场和温度梯度条件下,生长出从外观上来看没有缺陷,同成分(指熔体成分和晶体成分相同,而非化学计量配比)掺Mg铌酸锂晶体(MgCLN),测试了掺镁铌酸锂晶体的性能,并对该晶体进行了单畴化处理。在准相位匹配器件方面,本论文进行了如下的工作:首先在理论上阐述了相位匹配和准相位匹配的优缺点,从理论出发,结合CLN晶体的实际特性指标,设计输出3-5μm激光的周期结构和相应的调谐方式:分析了CLN晶体中畴结构的成核、扩展等过程,制备了周期极化器件,并进行了相应的倍频试验。更多还原

【Abstract】 The concept of quasi-phase matching has been proposed for over half of a century, but in practical applications, in particular the commercialization of products, it doesn’t progress significantly, which is mainly limited to quasi-phase-matched materials. In the past, preparation of this kind of materials was focused on the structure of the material in the same ingredients: Lithium tantalite, lithium neonate (CLN), potassium titanic phosphate (KTP) and other materials, but the main problems of these materials are the coercive field is higher, and the optical damage threshold is lower. In recent years, the main work has been focused on improving the shortcomings of these materials themselves, such as the growth of near-stoichiometric lithium tantalite and lithium neonate (SLT, SLN) is to improve key aspects of material performance, Crystal damage threshold raised l-2.coercive field is decreased by an order of magnitude. This paper looks for a relatively simple and practical way to grow Mg-doped lithium neonate crystal with a lower cost and the same composition, and produces a quasi-phase-matching device.This experiment in the appropriate temperature field and temperature gradient conditions, applying a better crystal Czochralski growth process parameters, better composition Mg-doped lithium neonate crystals (CLN) with no macro-defects and well optical homogeneity were prepared and their performance were tested, and the crystals were treated by single-domain processing. In the field of the quasi-phase matching devices, this paper carried out the following works: First of all, the strengths and weaknesses of the phase matching and quasi-phase matching were expounded in theory, combined with the actual characteristic indicators of CLN crystal, laser periodic structure with output of 3-5μm and the corresponding tuning methods were designed; the process of CLN crystal such as nucleation of domain structure, expansion and so on were analyzed, periodically poled devices were prepared, and the corresponding multiplier tests were carried out.更多还原