First-principles calculation of multiphoton absorption cross section of α-quartz under femtosecond laser irradiation
First-principles calculation of multiphoton absorption cross section of α-quartz under femtosecond laser irradiation
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DOI：
10.1007/s00339-016-9922-0
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
D. Yu;Lan Jiang;Feng Wang;L. Qu;Y. Lu
中科院分区：
文献类型：
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作者：
D. Yu;Lan Jiang;Feng Wang;L. Qu;Y. Lu
基于含时密度泛函理论的第一性原理计算被用来研究电离过程和电子激发。结果表明，在峰值强度I < 5 × 1013 W/cm ~ 2时，激发电子数服从幂律σ kIk，说明多光子电离起着关键作用。α-石英的多光子吸收截面σkis进一步计算为3.54 × 1011 cm − 3 ps −1（cm 2/TW）6。利用等离子体模型计算了损伤阈值注量，理论计算结果与实验结果吻合较好，验证了多光子吸收截面的计算结果。将计算得到的截面值应用于等离子体模型中，对损伤阈值注量进行了理论估算，与实验数据吻合较好，验证了多光子吸收截面的计算结果。初步建立的多尺度模型在激光加工模拟中显示了巨大的潜力。
Time-dependent density functional theory-based first-principles calculations have been used to study the ionization process and electron excitation. The results show that the number of excited electrons follows the power lawσkIkat peak intensities ofI< 5 × 1013W/cm2, indicating that the multiphoton ionization plays a key role. The multiphoton absorption cross section of α-quartzσkis further calculated to be 3.54 × 1011cm−3ps−1(cm2/TW)6. Using the plasma model, the theoretical results of the damage threshold fluences are consistent with the experimental data, which validates the calculated value of multiphoton absorption cross section. By employing the calculated cross section value in the plasma model, the damage threshold fluences are theoretically estimated, being consistent with the experimental data, which validates the calculated value of multiphoton absorption cross section. The preliminary multiscale model shows great potential in the simulation of laser processing.