Baset Farhana, Popov Konstantin, Villafranca Ana, Guay Jean-Michel, Al-Rekabi Zeinab, Pelling Andrew E, Ramunno Lora, Bhardwaj Ravi
Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5, Canada.
Opt Express. 2013 May 20;21(10):12527-38. doi: 10.1364/OE.21.012527.
We show that surface swelling is the first step in the interaction of a single femtosecond laser pulse with PMMA. This is followed by perforation of the swollen structure and material ejection. The size of the swelling and the perforated hole increases with pulse energy. After certain energy the swelling disappears and the interaction is dominated by the ablated hole. This behaviour is independent of laser polarization. The threshold energy at which the hole size coincides with size of swelling is 1.5 times that of the threshold for surface swelling. 2D molecular dynamics simulations show surface swelling at low pulse energies along with void formation below the surface within the interaction region. Simulations show that at higher energies, the voids coalesce and grow, and the interaction is dominated by material ejection.
我们表明，表面肿胀是单个飞秒激光脉冲与聚甲基丙烯酸甲酯（PMMA）相互作用的第一步。随后是肿胀结构的穿孔和材料喷射。肿胀和穿孔孔的尺寸随脉冲能量增加。在一定能量之后，肿胀消失，相互作用主要由烧蚀孔主导。这种行为与激光偏振无关。孔尺寸与肿胀尺寸一致时的阈值能量是表面肿胀阈值的1.5倍。二维分子动力学模拟显示，在低脉冲能量下表面肿胀，同时在相互作用区域内表面下方形成空洞。模拟表明，在较高能量下，空洞合并并生长，相互作用主要由材料喷射主导。
