【作者】 康玉琢；

【导师】 于建；

【作者基本信息】 天津大学 ， 物理电子学， 2007， 硕士

【摘要】 与角度相位匹配相比,准相位匹配能够利用晶体整个透光范围和晶体最大的非线性系数,所以其非线性转换效率较高。准相位匹配的实现,是通过人为的改变非线性晶体的结构,使其非线性系数周期化,从而满足相位匹配条件,这是近年来非线性光学研究的重要发展方向。外加电场极化法的出现,使得准相位匹配技术有了长足的发展,是一种通过对在铁电晶体表面光刻的周期电极施加电场来制作准相位匹配器件的方法。为得到理想的反转畴结构,必须对铁电晶体电致极化反转的原理及工艺进行深入的研究。论文分析了准相位匹配原理,从铁电晶体性质出发,深入研究了铁电晶体的极化反转机理,确定了极化反转波形;研制出用于制备准相位匹配器件的高压极化电源和用于温度调谐的温控器。本论文的主要工作如下:1、从非线性极化的原理出发,通过对麦克斯韦方程组的推导,得到了介质中三波互作用耦合波方程,并得到了准相位匹配倍频效率的计算公式。2、根据铁电晶体性质,深入研究了铁电晶体电致极化反转的机理,详细介绍了用外加电场极化法制备准相位匹配器件的过程。3、分析了制备周期极化铌酸锂(PPLN)与周期极化KTP(PPKTP)晶体对极化波形的要求,并研制了两套用于制备PPKTP的高压极化电源。一套高压极化电源可输出梯形波,三角波等多种波形,且输出波形的时间参数与电压参数可调;另一套可输出上升时间小于100μs的高压方波脉冲。电源用于KTP晶体的极化反转,取得了良好的实验结果。4、研究了光栅周期误差、占空比误差对准相位匹配器件倍频效率的影响;分析了准相位匹配器件的温度调谐,设计并制作了用于温度调谐的温控系统,该温控系统控制精度达到±0.1℃,最高工作温度可达220℃。5、进行了铁电晶体周期极化反转的实验研究;利用自行制备的PPLN和PPKTP器件进行了倍频通光实验,PPLN器件的倍频归一化效率为1.03%/W·cm,PPKTP器件的单通倍频归一化效率达1.69%/W·cm,接近理论的最大值;对准相位匹配器件周期调谐与温度调谐进行了实验研究。更多还原

【Abstract】 The whole wavelength rang and the biggest non-linearity coefficient of the ferroelectric crystals can be utilized by the Quasi-Phase-Matched technology, so the nonlinear conversion efficiency of the Quasi-Phase-Matching is higher than the angle phase-matching. The Quasi-Phase-Matched technology can be achieved by changing the structure of the crystal factitiously for making the non-linearity coefficient of the crystal periodic. It is the development direction of the nonlinear optics.The Quasi-Phase-Matched technology has developed fast since the Electric field periodic poling method appeared. It is a new technique to create periodically inversed domain structures in ferroelectric crystals to fabricate Quasi-Phase-Matched device. Investigation on the theory and technique of domain inversing is the basis of fabrication of ferroelectric crystals with ideal inversed domain structures. The dissertation analyzed the principle of Quasi-Phase-Matched, the character of ferroelectric crystals, and the theory of domain inversing, designed and fabricated the high voltage power supply for the manufacture of Quasi-Phase-Matching device and the heating controller for the temperature-tuned. Major contributions are as follows:1、Based on Maxwell’s equations, the couple mode equations between three light waves are educed and the formula of the efficiency of SHG is gained.2、Based on the character of ferroelectric crystals, investigated the theory and the technique of domain inversing and introduced the process of the fabrication of the Quasi-Phase-Matching device with Electric field periodic poling method.3、Analyzed the parameter of poling voltage which is for the fabrication of periodically poled lithium niobate (PPLN) and periodically poled KTP (PPKTP). Designed and fabricated two high voltage power supply for PPKTP. One can output trapezoid waveform and triangular waveform. Another can output square waveform whose rise time is short than 100μs. Many experiments were performed on KTP crystal by use of this power supply and the experimental results were gratifying.4、investigated the relationship between the error of the electrode period and the duty cycle and the SHG efficiency. Analyzed the temperature-tuned of the Quasi-Phase-Matched device. Designed and fabricated a heating controller for the temperature-tuned. Its control precision is±0.1℃and the highest working temperature is 220℃.5、Many poling experiments were performed on KTP and LN, and many SHG experiments were performed on the PPKTP and the PPLN which is fabricated by ourselves. The PPLN’s normalization efficiency of SHG is 1.03%/W·cm and the PPKTP’s is 1.69%/W·cm. The temperature-tuned experiments were also performed and the experimental results were analysed.更多还原