准相位匹配周期极化铌酸锂晶体微结构的研究.pdf

Abstract Abstract This work is supported妙 the National Natural Science Foundation of China and"863"project and Program for Changjiang Scholars and Innovative Research Team in University. Quasi-phase-matched (QPM) technology and its application are researched in this dissertation. Many formulas are worked out which are in agreement with the experimental data. And further more, this dissertation analyze and describe the characters of LiNb03 (LN) crystal and its periodically poled experiment in detail. LiNb03 crystal is one of the perfect materials to achieve the QPM technology. LN now develops rapidly because of its character of higher effective nonlinear coefficient. In recent years, LN crystal pulling and periodically poled LN (PPLN) fabrication technology has made much progress. So its application in nonlinear frequency conversion es more and more wide. Dissertation researches the basic theory of QPM as well as the method to achieve QPM technology. Major contributions are as follows: 1. Based on Maxwell equations and theory of nonlinear polarization, the couple mode equations are educed which is used to describe the interaction between three light waves in dielectric. And on the basis of this conclusion, the frequency conversion efficiency of SHG is analyzed in detail 2. The physical, chemical and ferroelectric characters of IN crystal are analyzed in this dissertation. Using the method of external electric field poling, the ferroelectric domain inverted process is described. Then, the character of LiNbO3 crystal and its periodically poled is analyzed from theory and validated from experiment. 3. Based on the grating diffraction theory, the duty cycle and refractive index change of the periodically poled microstructure (PPMS) crystal are studied theoretically by light diffraction efficiency. Key words: Quasi-Phase-Matched (QPM), Periodically Poled LiNb03 (PPLN),Second-Harmonic Generation (SHG), External Elect