Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

作     者：周吉 贺志宏 马宇 董士奎 

作者机构：School of Energy Science and EngineeringHarbin Institute of Technology 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2015年第24卷第9期

页      面：223-234页

核心收录：

学科分类：070207[理学-光学] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 08[工学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.51176039) 

主　　题：birefringence electro-optic modulators thermo-optic effects 

摘      要：We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave＇s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are *** of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer boundary con