2021 Fiscal Year Final Research Report
Integrated thermal and electronic modeing of ultrashort pulse laser processing of transparent materials
| Project/Area Number |
18H01379
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 19020:Thermal engineering-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | レーザ / 透明材料 / 加工閾値 / 熱工学 |
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| Outline of Final Research Achievements |
Ultrashort pulse laser processing of transparent materials has been investigated by considering the thermal-electronic mechanism both experimentally and numerically. Fused silica has been chosen for the sample. Experiments show unique characteristics of the ablation threshold with pulse width dependence and the two stage behavior of the ablation hole depth as a function of fluence. Numerical calculation has been developed by combining the rate eq. of the electron number density, BPM scheme for the electric field, and the two temperature model for the electron and lattice temperature calculation to explain the fluence and the pulse width dependence. Initial target is therefore fulfilled by showing the importance of the combined electronic and thermal modeling on the problem.
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| Free Research Field |
熱工学
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| Academic Significance and Societal Importance of the Research Achievements |
ガラスなどの透明材料はスマートフォンやディスプレイ、微量試薬検査など膨大な応用があるが、一般に硬くて脆い材料が多いため機械加工が困難で、レーザ加工が期待される。しかしながら「透明」材料であるため、レーザ光を吸収させ加工に至らせる現象が複雑で、意図した加工を施すための条件設定が極めて複雑である。本研究ではこの課題に理論的説明を与えるため、非線形光学効果と呼ばれる現象により光吸収が強くなる１兆分の１秒程度以下の超短パルスで発光するレーザを用いた加工現象について、従来から言われてきた電子の挙動と、条件によって共存する熱的な挙動の両者を統一的に論じることの重要性を提起し、実験と理論計算により検証した。
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