铌酸锂微纳波导中的二阶非线性光学效应研究进展  

Advances in second-order nonlinear optical effects of lithium niobate micro/nano waveguides

作　　者：吴肖 郝振中 薄方 张国权 许京军 Xiao Wu;Zhenzhong Hao;Fang Bo;Guoquan Zhang;Jingjun Xu(Ministry of Education Key Laboratory of Weak-Light Nonlinear Photonics,TEDA Institute of Applied Physics,School of Physics,Nankai University,Tianjin 300457,China)

机构地区：[1]南开大学物理科学学院,泰达应用物理研究院,弱光非线性光子学教育部重点实验室,天津300457

出　　处：《科学通报》2022年第33期3915-3927,共13页Chinese Science Bulletin

基　　金：国家重点研发计划(2019YFA0705000);国家自然科学基金(11734009,12004197,12034010,12074199,12134007,92050111,92050114)资助。

摘　　要：由于具有优秀的线性和非线性光学特性,铌酸锂薄膜(lithium niobate thin film, LNTF)被视为一个很有前途的集成光子学平台.作为集成光学系统的基本单元,铌酸锂微纳波导不仅作为传输、控制器件被研究,也展现出优秀的二阶非线性光学特性.本文综述了铌酸锂薄膜微纳波导二阶非线性效应研究的最新进展,以倍频转换效率为例,讨论了影响二阶非线性转换效率的因素,全面总结了LNTF(周期极化)波导的制备,高效、可调谐、宽带二次谐波产生,自发参量下转换研究的现状,并对未来的研究方向进行了展望.Lithium niobate(LiNbO3, LN) crystal has a large second-order nonlinear coefficient(d33=25.2 pm/V@1064 nm), wide transparent window(0.35–5 μm), and stable periodic microdomain structure preparation, which is a good platform for the study and application of second-order nonlinear optical effects. Lithium niobate thin film(LNTF) is regarded as a promising integrated photonics platform due to its excellent linear and nonlinear optical properties. As the basic unit of an integrated optical system, lithium niobate micro/nano waveguide has been studied as a transmission and control device, and it shows excellent second-order nonlinear optical characteristics.The second-order nonlinearity plays an important role in modern optics, including second-harmonic generation(SHG),sum-and difference-frequency generation, parametric down conversion, and parametric oscillation. Efficient and compact wavelength converters based on second-order nonlinearity are key components for a wide range of applications, including entangled photon sources, optical parametric oscillators, and optical parametric amplifiers. The second-order nonlinear polarization intensity is proportional to the square of the electric field intensity. Micro/nano optical waveguides can improve the light intensity in the device through the local characteristics of the spatial light field, to improve the conversion efficiency of the nonlinear processes. And significantly enhanced electric field strength makes the normalized nonlinear conversion efficiency of LNTF waveguides exceed that of the reverse proton exchange lithium niobate waveguides(frequency conversion efficiency 150% W–1cm–2@1550 nm) by one order of magnitude. The nonlinear conversion efficiency of LNTF micro/nano waveguides can be further improved through mode phase matching(MPM) or quasi-phase matching(QPM) to optimize the spatial overlap between the eigenmodes involved in the nonlinear process. The detailed theory, fabrication and application were demonstrated in the manuscript as follows:(1) The

关 键 词：铌酸锂 微纳光波导 二阶非线性 倍频 参量下转换 集成光学 

分 类 号：TQ131.11[化学工程—无机化工] TB383.2[一般工业技术—材料科学与工程] O437[机械工程—光学工程]