Žemaitis Andrius, Gaidys Mantas, Gečys Paulius, Gedvilas Mindaugas
Department of Laser Technologies (LTS), Center for Physical Sciences and Technology (FTMC), Savanorių Ave. 231, 02300, Vilnius, Lithuania.
Sci Rep. 2024 Mar 7;14(1):5614. doi: 10.1038/s41598-024-54928-7.
In this work, a bi-stable behavior of laser ablation efficiency and quality was controlled by fluence and burst length. The plasma shielding of incoming laser radiation caused sudden jumps with a significant decrease in ablation efficiency for every even number of pulses in the burst. The attenuation of incoming laser radiation by plasma created by the previous pulse was incorporated into the toy model of burst ablation efficiency. The mathematical recurrence relation has been derived for the first time, binding ablation efficiency for the next pulse with the efficiency of the previous pulse, which predicts bi-stability, as well as sudden jumps occurring in ablation efficiency depending on the number of pulses in burst with the response to changes of the control parameter of peak laser fluence in the pulse. The modeling results using new recurrence relation showed stable and bi-stable ablation efficiency depending on burst fluence and the number of pulses, which agreed well with experimental data. The extremely efficient laser ablation has been achieved by optimizing the shielding effect using three pulses in the burst.
在这项工作中，激光烧蚀效率和质量的双稳态行为由能量密度和脉冲串长度控制。入射激光辐射的等离子体屏蔽导致在脉冲串中每个偶数脉冲时出现突然跳跃，烧蚀效率显著降低。前一个脉冲产生的等离子体对入射激光辐射的衰减被纳入脉冲串烧蚀效率的简化模型。首次推导了数学递推关系，将下一个脉冲的烧蚀效率与前一个脉冲的效率联系起来，该关系预测了双稳态以及烧蚀效率中根据脉冲串中的脉冲数出现的突然跳跃，以及对脉冲中峰值激光能量密度控制参数变化的响应。使用新的递推关系的建模结果表明，根据脉冲串能量密度和脉冲数，烧蚀效率呈现稳定和双稳态，这与实验数据吻合良好。通过在脉冲串中使用三个脉冲优化屏蔽效应，实现了极高效率的激光烧蚀。
