Analytical solution to incident angle quasi-phase-matching engineering for second harmonic generation in a periodic-poled lithium niobate crystal  

作　　者：洪丽红 邱雅婷 李晓霓 陈宝琴 李志远 Li-Hong Hong;Ya-Ting Qiu;Xiao-Ni Li;Bao-Qin Chen;Zhi-Yuan Li(State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China [2]School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510640,China

出　　处：《Chinese Physics B》2024年第2期115-123,共9页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.11974119);the Science and Technology Project of Guangdong Province,China(Grant No.2020B010190001);the Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06C594);the National Key Research and Development Program of China(Grant Nos.2018YFA,0306200,and 2019YFB2203500);the Science and Technology Program of Guangzhou City(Grant No.2023A04J1309).

摘　　要：Phase matching or quasi-phase matching(QPM)is of significant importance to the conversion efficiency of second harmonic generation(SHG)in artificial nonlinear crystals like lithium niobate(LN)crystal or microstructured nonlinear crystals like periodic-poled lithium niobate(PPLN)crystals.In this paper,we propose and show that the incident angle of pump laser light can be harnessed as an alternative versatile tool to engineer QPM for high-efficiency SHG in a PPLN crystal,in addition to conventional means of period adjusting or temperature tuning.A rigorous model is established and analytical solution of the nonlinear conversion efficiency under the small and large signal approximation theory is obtained at different incident angles.The variation of phase mismatching and walk-off length with incident angle or incident wavelength are also explored.Numerical simulations for a PPLN crystal with first order QPM structure are used to confirm our theoretical predictions based on the exact analytical solution of the general large-signal theory.The results show that the narrow-band tunable SHG output covers a range of 532 nm–552.8 nm at the ideal incident angle from 0°to 90°.This theoretical scheme,fully considering the reflection and transmission at the air-crystal interface,would offer an efficient theoretical system to evaluate the nonlinear frequency conversion and help to obtain the maximum SHG conversion efficiency by selecting an optimum incident wavelength and incident angle in a specially designed PPLN crystal,which would be very helpful for the design of tunable narrow-band pulse nanosecond,picosecond,and femtosecond laser devices via PPLN and other microstructured LN crystals.

关 键 词：nonlinear frequency conversion transmission REFLECTION lithium niobate 

分 类 号：O741[理学—晶体学] TN249[电子电信—物理电子学]