超短激光脉冲序列烧蚀镍薄膜的研究

Study on ablation of Ni film by ultrashort laser pulse-train

超短(飞秒)激光脉冲序列技术能有效地提高激光加工金属的加工精度,它在微/纳制造中具有重要的理论意义和生产价值。为了研究脉冲间隔对激光烧蚀金属加工精度的影响,以过渡金属镍为研究对象,采用双温模型和分子动力学模拟相结合的方法,对飞秒激光脉冲序列(脉冲间隔不同)烧蚀金属镍的过程、现象进行了研究,取得了脉冲序列烧蚀镍薄膜的动态表层电子温度和晶格温度随时间演化的数据和烧蚀区域在不同时刻的快照。结果表明,一定范围内,随着脉冲间隔的增加,脉冲序列烧蚀镍薄膜所产生的纳米粒子更加均匀,烧蚀平面更加平整,初始熔化速度、烧蚀率呈降低趋势,有利于提高加工的精度。

Micromaching by ultrashort laser pulse-train can effectively improve femtosecond laser ablation of metal,which are important both theoretically and practically in micro/nano-laser fabrication applications.In order to study the effect of separation of pulse on the accuracy of laser ablation,the phenomena and process of laser ablation with different separation of pulse train were studied in detail by combining the molecular dynamic simulation and two-temperature model,the electron and lattice temperatures of the layers next to dynamic film surfaces and the snapshots of nickel thin films irradiated by the femtosecond laser pulse trains were obtained.The result is that,within a certain range,as the increase of the separation of pulse,femtosecond pulse train laser ablation of Ni films can apparently cause more flat ablation plane,slower initial melting speed,smaller and more uniform nanoparticles,smaller ablation ratio,which can effectively improve femtosecond laser ablation of metal.