飞秒激光烧蚀LiNbO_3晶体的形貌特征与机理研究  

Morphology and mechanism of femtosecond laser-induced structural changes in lithium niobate crystal

作　　者：余本海[1] 戴能利[1] 王英[1] 李玉华[1] 季玲玲[1] 郑启光[1] 陆培祥[1] 

机构地区：[1]华中科技大学武汉光电国家实验室激光科学与技术部,光电子科学与工程学院武汉430074

出　　处：《物理学报》2007年第10期5821-5826,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10574050);高等学校博士学科点专项科研基金(批准号:20060487006)资助的课题~~

摘　　要：采用了不同能量的单脉冲和多脉冲飞秒激光对LiNbO3晶体进行烧蚀,并刻蚀了表面衍射型光栅.通过扫描电镜和原子力显微镜观察了烧蚀点的形貌特征,首次发现利用单束飞秒激光脉冲对LiNbO3晶体烧蚀,可以得到超衍射极限的烧蚀点,当聚焦光斑直径约为2μm、能量为170nJ的单脉冲飞秒激光作用时,烧蚀点的直径约为400nm,100nJ,17个脉冲作用时烧蚀点的直径约为800nm.同时可以观察到在能量较低的多脉冲飞秒激光作用下,LiNbO3晶体呈现出大约200nm周期性分布的波纹状结构.实验结果表明,选择合适参数的飞秒激光脉冲可以对LiNbO3晶体进行超衍射极限加工,这对于利用飞秒激光制作LiNbO3基质的微纳光电子器件有十分重要的意义.The morphology and mechanism of lithium niobate （LiNbO3） crystal ablated by a femtosecond laser pulse have been studied. The ablated spots and surface diffraction grating have been examined by means of scanning electron microscopy （SEM） and atom force microscopy （AFM）. Sub-diffraction limit spots in LiNbO3 crystal ablated by femtosecond laser have been obtained. The diameters of ablation spots are 400 nm and 800 nm when 170 nJ single pulse and 100 nJ 17 pulses are used, respectively. There are ripples with about 200 nm periodic on the bottom surfaces of the spots at low laser energy. The result shows that the sub-diffraction limit structures may be formed by the multi-photon excitation, and the femtosecond laser ablation is an innovative tool for manufacturing LiNbO3-based optical devices.

关 键 词：飞秒激光 LiNbO晶体 衍射极限 烧蚀阈值 

分 类 号：O734[理学—晶体学]