Induced structure control in transparent materials by combining multi-point simultaneous irradiation and energy modulation of pulsed laser

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02482
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Kyoto University
• Principal Investigator: Miura Kiyotaka 京都大学, 工学研究科, 教授 (60418762)
• Co-Investigator(Kenkyū-buntansha): 清水 雅弘 京都大学, 工学研究科, 助教 (60704757)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: レーザー / ガラス / 単結晶

Outline of Final Research Achievements

The thermal diffusion equation was used to simulate the time variation of the temperature distribution in the molten region during multi-point simultaneous irradiation. Furthermore, the spatial viscosity distribution was calculated from the obtained temperature gradient using the relationship between viscosity and temperature given by Fulcher's equation.
We have established a transient stress observation system that can observe stress changes on the picosecond to nanosecond scale. Furthermore, a theoretical analysis of the stress distribution was performed by elastic dynamics simulation.
A polarization high-speed imaging camera was used to observe the temporal change in the magnitude of birefringence generated inside the glass during laser scanning. The moving phenomenon (vertical movement) observed with a high-speed camera was reproduced by FDTD calculation, using the plasma generated at the laser focusing part as a perfectly conductive sphere.

Free Research Field

材料化学

Academic Significance and Societal Importance of the Research Achievements

非晶質内部の空間的な局所温度勾配制御による元素分布領域の形状・サイズ制御や単結晶内部における衝撃波の干渉を利用したクラックの伸長制御を実験的に調べ、その挙動をシミュレーションにより再現する手法を確立したことで、現象のメカニズムの解明に加えプロセス条件や材料設計においても重要な知見を得ることが出来る。さらに、れらの現象をパルスエネルギーに変調をかけた状態で連続的に材料内部に誘起させる方法と組み合わせることで、新規な材料プロセッシングの開発や、材料への新たな機能発現が期待できる。