飞秒激光微爆加工铌酸锂晶体  

Study on LiNbO_3 fabrication by femtosecond laser induced micro-explosion

作　　者：肖诗洲[1] 郭锐[1] 程光华[2] 黄文浩[1] 

机构地区：[1]中国科学技术大学精密机械与精密仪器系,安徽合肥230027 [2]中国科学院西安光学机械精密机械研究所瞬态光学国家重点实验室,陕西西安710068

出　　处：《中国科学技术大学学报》2008年第5期558-562,共5页JUSTC

基　　金：国家自然科学基金(50275140,50335050)资助

摘　　要：利用紧聚焦飞秒激光脉冲入射到铌酸锂(LiNbO3)晶体中引起微爆,可以在晶体内部进行微爆加工.与各向同性的熔融石英不同,因为铌酸锂晶体的各向异性,微爆加工点在垂直晶轴的截面上表现出强烈的各向异性.我们利用狭缝光阑对入射飞秒高斯光束进行整形,改变了光束的能量分布,成功地减小加工点的各向异性,获得尺寸较一致的微爆单元.另外发现由于折射率失配的存在,飞秒脉冲激光聚焦深度不一样时,微爆加工点在沿晶轴方向的截面形状和尺寸都有很大的变化,对此也进行了理论和实验上的分析.A tightly focused femtosecond laser pulse is used to initiate micro-explosion in LiNbO3 crystal. Unlike the isotropic samples such as silica, the top morphology of the micro explosion region perpendicular to the crystal axis of LiNbO3 shows strong anisotropy. In order to obtain more isotropic explosion fabrication spots, the injecting femtosecond laser is shaped utilizing a rectangular aperture which can change the power intensity distribution in both XY and XZ cross sections. By optimizing the rectangle ratio, the anisotropic shape of the explosion spot is weakened and more coincident in both directions. Further more, the change of micro explosion morphology in the section along the crystal axis at different depths due to refractive index mismatch is discussed.

关 键 词：铌酸锂 微爆 激光微加工 折射率失配 

分 类 号：TN249[电子电信—物理电子学]