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摘要：铌酸锂(LiNb03)晶体是一种集光电、压电、光折变等效应于一体的人工晶体材料。可纯铌酸锂晶体的抗光折变能力并不强，限制了该晶体在很多光学仪器方面的应用。在纯铌酸锂晶体中掺入杂质可以有效改善晶体抗光折变等各项能力。如掺镁或铟可提高晶体的抗光折变能力，使得晶体可以适用于Q开关以及倍频；掺铜可以大大提高铌酸锂晶体的光折变能力，有利于全息储存；掺钛则可以改变晶体的折射率，用于光波导。另外铌酸锂晶体是一种应用十分灵活的激光活性介质，稀土离子的一项特点是其具备丰富的能级结构，故将其经常作为激活离子掺杂到晶体中，掺入不同稀土离子就能够发出不同的特征频率的激光，最常见的发光掺杂为铒和镱、钕、铕，因为发光效率不高，所以将铌酸锂晶体作为单独发光介质而被应用的报道不多，但是利用铌酸锂晶体的优良光电性能以及非线性光学性能，我们选择将它们和发光特性结合在一起，便可以使二者相得益彰。为了开发出性能更好的抗光折变掺杂铌酸锂晶体，此次实验选择尝试用两种三价掺杂离子进行共掺：Y3+、Tm3+。本论文研究了钇、铥共掺铌酸锂晶体的生长及其基本物理性能。63448
使用固相法（提拉法），我们成功生长了掺Y:Tm量为1.0:9.0mol%、2.0:8.0mol%、3.0:7.0mol%、4.0:6.0mol%、5.0:5.0mol%和6.0:4.0mol%的同成分铌酸锂晶体。使用XRD、OH-红外吸收光谱、紫外可见吸收光谱和上转换荧光光谱研究各稀土离子对于晶体结构缺陷和上转换荧光性能的影响。研究结果表明Y3+和Tm3+离子在荧光色度调节方面具有非常重要的作用。
毕业论文关键词： 铌酸锂晶体；稀土掺杂；晶体生长；抗光折变；抗光损伤
Study on the growth and properties of Y/Tm—doped LiNb03 crystals
Abstract: Lithium niobate is one of the most promising synthetic crystals for its excellent physical properties such as electro-optic， thermal—optic and photorefractive effects. Unfortunately，photorefraction, originated by light—induced refractive-index changes，limits its usage on some optical devices under high light intensities. Such as MgO and indium can improve the ability of anti photorefractive crystal, is suitable for Q switching and frequency doubling; Cu doped photorefractive crystal can improve the ability, favorable for holographic storage; refraction Ti can change the crystal rate for optical waveguide. In addition lithium niobate is a laser active medium application is very flexible, a characteristic of rare earth ions is its rich energy level structure, so it is often used as active ions doped into the crystal, doped with different rare earth ions can emit characteristic of different frequency laser light, is the most common and erbium doped ytterbium, neodymium, europium, because the luminous efficiency is not high, not so much will separate the light emitting medium is used as lithium niobate crystal reports, but the use of lithium niobate crystal optoelectronic and nonlinear optical properties, and their luminescence properties together, it can make the two complement each other. In order to explore the better performance of the photorefractive doped lithium, we choose to try to use two kinds of trivalent doped ions Co doped: Y3+, Tm3+. This paper studied and the basic physical properties of yttrium and thulium Co doped lithium niobate crystal growth.
Using the solid phase method, we have successfully grown the Y:Tm content of 1.0:9.0mol%, 2.0:8.0mol%, 3.0:7.0mol%, 4.0:6.0mol%, 5.0:5.0mol% and 6.0:4.0mol% of the same composition of lithium. Effects of rare earth ions on crystal structure defects and up conversion fluorescence properties were studied using XRD, OH- infrared absorption spectroscopy, ultraviolet visible absorption spectroscopy and up conversion fluorescence spectroscopy. The results show that Y3+ and Tm3+ ions have a very important role in the regulation of fluorescent color.