The manufacture of micro–nano structures in transparent dielectrics is becoming increasingly important due to the applications in medical and biological sciences. The femtosecond pulsed laser, with its selectivity, high precision, and three-dimensional direct writing nature, is an ideal tool for this processing technology. In this paper, an improved model for the prediction of ablation crater shape and fluence threshold in femtosecond laser processing of fused silica is presented, in which self-trapping excitons and electrons' relaxation are involved to depict ionization process, Thornber's and Keldysh's models are employed to estimate ionization rate precisely, and a novel ablation criterion is proposed to judge ablation. Moreover, the relationship between the ablation fluence threshold and laser pulse duration is investigated with three different extrapolation methods. The results indicate that no matter which extrapolation method is employed, the ablation fluence thresholds predicted by the presented model agree with the published data.
A Prediction Model for Ablation Fluence Threshold in Femtosecond Laser Processing of Fused Silica
Shanghai Jiao Tong University,
Shanghai 200240, China
Contributed by the Manufacturing Engineering Division of ASME for publication in the JOURNAL OF MICRO- AND NANO-MANUFACTURING. Manuscript received January 16, 2017; final manuscript received May 17, 2017; published online June 9, 2017. Assoc. Editor: Nicholas Fang.
Wang, H., and Shen, H. (June 9, 2017). "A Prediction Model for Ablation Fluence Threshold in Femtosecond Laser Processing of Fused Silica." ASME. J. Micro Nano-Manuf. September 2017; 5(3): 031006. https://doi.org/10.1115/1.4036890
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