像差预补偿的铌酸锂晶体内部激光直写(特邀)  

Aberration Precompensation Laser Direct Writing Within Lithium Niobate Crystals(Invited)

作　　者：王天新 张勇 Wang Tianxin;Zhang Yong(National Laboratory of Solid State Microstructures,Nanjing 210093,Jiangsu,China;College of Engineering and Applied Sciences,Nanjing University,Nanjing 210093,Jiangsu,China;School of Physics,Nanjing University,Nanjing 210093,Jiangsu,China)

机构地区：[1]固体微结构物理国家重点实验室,江苏南京210093 [2]南京大学现代工程与应用科学学院,江苏南京210093 [3]南京大学物理学院,江苏南京210093

出　　处：《激光与光电子学进展》2024年第11期1-7,共7页Laser & Optoelectronics Progress

基　　金：中央高校基本业务费(021314380226,021314380191)。

摘　　要：集成光电器件正由传统的二维构型向全空间维度发展,激光直写凭借其独特的三维加工优势在全维度光子芯片的发展中发挥了重要的作用。铌酸锂是近年来受到广泛关注的高性能光电材料,但由于界面间的大折射率失配引入像差,极大地影响了在铌酸锂晶体内部三维激光直写的精度。基于自适应光学原理的像差补偿技术可以对激光光束进行精确的波前控制,为实现聚焦光斑的像差校正提供了可行方案。针对铌酸锂内部进行三维激光加工的特点,由点扩散函数出发设计了对像差进行预补偿的理论模型,搭建了基于空间光调制器的像差预补偿激光加工系统,在实际测试中表征并对比了像差补偿后的结构加工效果。结果表明,优化像差补偿参数后,在铌酸锂表面以下110μm深度范围内获得了均匀性良好、无明显聚焦次点的激光改性结构。这一方案为在铌酸锂晶体内部实现高质量、全维度、大深度激光直写提供了可行性。The evolution of integrated optoelectronic devices has transitioned from conventional two-dimensional configurations to full spatial dimensions.Laser direct writing,with its unique three-dimensional processing capabilities,has significantly contributed to the advancement of photonic chips.Lithium niobate has garnered considerable interest due to its excellent material properties.Nonetheless,the large refractive index mismatch at the interface between lithium niobate and air considerably affects the accuracy of laser direct writing within lithium niobate crystals.Adaptive opticsbased aberration correction emerges as a practical approach to address this challenge.In this study,we begin with an analysis of the point spread function and proceed to derive theoretical precompensation functions.In experiments,we employ a spatial light modulator to implement aberration correction.We systematically compare and characterize grating structures processed with and without aberration correction.Employing aberration correction at a depth of 110μm beneath the surface results in the formation of uniform laser-modified structures devoid of focal subpoints.The incorporation of adaptive optics into the laser direct writing process paves the way for the fabrication of high-quality three-dimensional photonic structures within lithium niobate crystals.

关 键 词：铌酸锂 飞秒激光直写 自适应光学 像差校正 泽尼克多项式 

分 类 号：O437[机械工程—光学工程]