飞秒激光调控晶体材料光学非线性的研究进展  

Research Advances on Femtosecond Laser Modulation of Optical Nonlinearityin Crystal Materials(Invited)

作　　者：张彬 陈峰[1] Zhang Bin;Chen Feng(State Key Laboratory of Crystal Materials,School of Physics,Shandong University,Jinan 250100,Shandong,China)

机构地区：[1]山东大学物理学院晶体材料国家重点实验室,山东济南250100

出　　处：《光学学报》2024年第17期234-249,共16页Acta Optica Sinica

基　　金：国家自然科学基金(12204274,12174222,12361141815);山东省自然科学基金(ZR2022QA033,ZR2021ZD02)。

摘　　要：非线性晶体是非线性光学领域中实现波长/频率转换的重要载体。通过周期性地调控非线性晶体的光学非线性,可以按需制备多种非线性光子晶体结构,从而实现特定波长激光高效频率转换和非线性光束整形等应用。飞秒激光直写技术具有精度高、速度快以及真三维加工等特点,在材料微纳加工领域得到了广泛的应用。用透镜或显微物镜将飞秒激光聚焦到非线性晶体内部,可以对激光焦点处的晶体非线性进行调控;通过设置并优化飞秒激光加工参数,能够实现特定三维非线性光子晶体的快速高效制备。本文从非线性晶体的光学非线性调控、飞秒激光直写技术出发,简要介绍了飞秒激光直写非线性光子晶体的最新研究进展,并对几个潜在的研究方向进行了展望。Significance Nonlinear optical crystals exhibit secondary or higher-order nonlinear optical effects under strong laser fields and are commonly used for wavelength/frequency conversion of lasers.They have played a vital role in various fields,such as nonlinear optics,laser communication,laser technology,and military medicine.Common nonlinear optical crystals include lithium niobate(LiNbO_(3),abbreviated as LN),lithium tantalate(LiTaO_(3),abbreviated as LT),and potassium titanium phosphate(KTiOPO4,abbreviated as KTP).Key indicators for evaluating the performance of nonlinear crystal materials include large nonlinear optical coefficients,wide transparency range,and high damage threshold.Modulation of nonlinear coefficients is crucial for enhancing the performance of these materials.For instance,by periodically adjusting the nonlinear coefficients(i.e.,spontaneous polarization or ferroelectric domains)of the multifunctional ferroelectric LiNbO_(3)crystal,nonlinear photonic crystals(NPCs)could be fabricated,significantly improving the conversion efficiency of processes like frequency doubling and spontaneous parametric down conversion.Currently,the primary techniques for fabricating NPCs in LiNbO_(3)crystals are electrical poling and optical poling.While electrical poling yields excellent performance and is commercialized,its technological process is complex and requires custom masks for each NPC design,increasing manufacturing costs.Traditional electrical poling techniques have demonstrated unique strengths in creating one-dimensional(1D)and two-dimensional(2D)NPCs.However,it encounters significant hurdles when attempting to fabricate three-dimensional(3D)NPCs,presenting substantial experimental challenges within the field of nonlinear optics over the past two decades.There are two primary types of optical poling techniques:light-assisted poling and all-optical poling.Light-assisted poling is characterized by the use of ultraviolet laser irradiation to facilitate the poling process.In contrast,all-optical poling empl

关 键 词：超快光学 微纳加工 飞秒激光直写 晶体材料 非线性频率转换 

分 类 号：O436[机械工程—光学工程]