高能强场太赫兹源与铌酸锂晶体  

High⁃Energy,Strong⁃Field Terahertz Source and Lithium Niobate Crystal

作　　者：韩文斌 孙德辉 王蒙 李陈哲 刘首廷 刘宏 Han Wenbin;Sun Dehui;Wang Meng;Li Chenzhe;Liu Shouting;Liu Hong(Institute for Advanced Interdisciplinary Research(iAIR),University of Jinan,Jinan 250022,Shandong,China;State Key Laboratory of Crystal Materials,Shandong University,Jinan 250100,Shandong,China;Shandong Hengyuan Semiconductor Technology Co.,Ltd.,Jinan 271100,Shandong,China)

机构地区：[1]济南大学前沿交叉科学研究院,山东济南250022 [2]山东大学晶体材料国家重点实验室,山东济南250100 [3]山东恒元半导体科技有限公司,山东济南271100

出　　处：《中国激光》2023年第17期23-33,共11页Chinese Journal of Lasers

基　　金：山东省自然科学基金重大基础研究项目(ZR2021ZD20);国家自然科学基金(51802113);山东省高等学校青创团队计划、中央引导地方科技发展专项资金(YDZX2022074)。

摘　　要：高能强场太赫兹(THz)源在国土安全、通信雷达、生物医疗等领域有重要的应用价值。然而,一直以来THz源的辐射输出能量小、转化效率低,阻碍了强场THz前沿科学与应用研究的发展。基于铌酸锂倾斜波前技术,飞秒激光抽运铌酸锂晶体有望实现能量更高的极端强场THz输出。从材料角度阐述了铌酸锂强场THz源产出的研究进展,总结了强场THz源对铌酸锂晶体的性能要求:均匀掺镁铌酸锂、低浓度掺镁近化学计量比铌酸锂、大口径铌酸锂晶体。最后,介绍了近年来周期极化铌酸锂和铌酸锂单晶薄膜等微纳结构的调控在THz源领域的应用研究。Significance Terahertz(THz)radiation,with the frequency lying between microwave and infrared,has rich information content,high temporal-spatial coherence,low photon energy,strong penetration,and high bandwidth.Therefore,the THz radiation holds immense application value in fields such as national security,satellite communications,non-destructive material testing,and medical imaging.However,the current THz sources with the small energy cannot meet the demand of scientific and application research.The strong-field THz source,with peak electric fields larger than 1 MV/cm,low photon energy,and high temporal resolution,has become the research target of many scientists.Up to now,the THz radiation output through photonics has attracted enough interests due to its ultra-fast resolution and ultrawide spectrum.The lithium niobate(LiNbO3,LN)crystal,exhibiting weak THz absorption,a large second-order nonlinear coefficient,and stable physical and chemical properties,is one of the first materials to achieve THz pulse output.To be noted,since Hebling and co-workers proposed the tilted-pulse-front technique,the LN THz source has been greatly improved in terms of output power and conversion efficiency.Recently,Wu and co-workers achieved an ultra-strong LN-THz radiation with a single pulse energy of 13.9 mJ,a conversion efficiency of 1.2%,and a peak field strength of 7.5 MV/cm.Apart from the laser technique,the property of LN crystal is the main factor for the THz source.Moreover,the traditional LN crystal is a classical non-stochiometric crystal with high-concentration intrinsic defects,which greatly affects the crystal property.Correspondingly,some improvement methods have been exploited including magnesium-doped and near-stochiometric LN(SLN)crystals.Therefore,in order to promote the development of LN THz source,we analyze the performance requirements and development direction of LN crystals for strongfield THz sources.In 2008,Stepanov et al.used the large size MgO∶SLN crystal pumped by the pulsed laser with 6-mm-diameter spot

关 键 词：非线性光学 太赫兹波 铌酸锂晶体 强场太赫兹辐射 均匀掺镁 化学计量比 大口径 

分 类 号：O437[机械工程—光学工程]