Case study on the ultrafast laser ablation of thin aluminum films: dependence on laser parameters and film thickness
Case study on the ultrafast laser ablation of thin aluminum films: dependence on laser parameters and film thickness
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铝薄膜超快激光烧蚀案例研究：对激光参数和薄膜厚度的依赖性
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发表时间：
2016
期刊：
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通讯作者：
A. Horn
中科院分区：
文献类型：
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作者：
M. Olbrich;E. Punzel;R. Roesch;R. Oettking;B. Muhsin;H. Hoppe;A. Horn
使用超短脉冲激光辐射的激光烧蚀允许以非常高的空间分辨率去除薄膜，并且以高重复率以及高吞吐量工作。研究了聚焦飞秒激光（λ = 1028 nm，tH = 200 fs，sech 2，pf = 1 MHz）对浮法玻璃上铝薄膜的超快烧蚀，烧蚀过程是每点脉冲数Np（1-10）和薄膜厚度d（30-300 nm）的函数。据观察，两个阈值推导出同时与厚度大于100 nm的薄膜，通过照射的金属与单一脉冲激光辐射表现出高斯强度分布：一个阈值为温和的烧蚀Hthr，温和和其他强烧蚀Hthr，强。改变每个点的脉冲数的多脉冲照射确定了Jee等人描述的孵育效应（J Opt Soc Am B 5（3）：648，1968）。该模型应用于轻度和强烈消融的阈值。此外，由于热积累，改变层厚度降低了薄膜的阈值。为了量化实验数据，进行了数值模拟求解的耦合传热方程的双温模型。基于Brückner等人提出的模型（J Appl Phys 66：1326，1989），提出了一种新的方法，包括反射率的温度依赖性。模拟结果与实验数据定性吻合较好。对脉冲间隔时间为1-300 ps的双脉冲进行了理论研究，并与单脉冲进行了比较。
Laser ablation using ultra-short pulsed laser radiation allows the removing of thin films with very high spatial resolution, and working with high repetition rate as well with high through-put. The ultrafast ablation of thin films of aluminum on float glass is investigated using focused femtosecond laser radiation (λ = 1028 nm, tH = 200 fs, sech2, pf = 1 MHz) as function of the number of pulses Np per point (1–10) and the film thickness d (30–300 nm). It is observed that two thresholds are derived simultaneously for thin films with a thickness thicker than 100 nm by irradiating the metal with single pulsed laser radiation exhibiting a Gaussian intensity distribution: one threshold for gentle ablation Hthr,gentle and the other for strong ablation Hthr,strong. Multi-pulse irradiation varying the number of pulses per point identifies the incubation effect described by Jee et al. (J Opt Soc Am B 5(3):648, 1968). This model was applied on the thresholds for gentle and strong ablation. Also, varying the layer thickness reducing the thresholds for thin films due heat accumulation. To quantify the experimental data, numerical simulations solving the coupled heat transfer equation of the two-temperature model were performed. A new approach including the temperature dependence of the reflectivity is presented based on the model proposed by Brückner et al. (J Appl Phys 66:1326, 1989). The results of the simulation fit qualitative well to the experimental data of gentle ablation. Theoretical investigation for double pulses with a variable pulse separation time of 1–300 ps were performed in comparison with a single pulse.