| Project/Area Number |
16360068
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Production engineering/Processing studies
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
OHMURA Etsuji Osaka University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (90144435)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MORI Yusuke Osaka University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (90252618)
SANO Tomokazu Osaka University, Graduate School of Engineering, Assistance Professor, 工学研究科, 助手 (30314371)
竹野 祥瑞 三菱電機(株), 生産技術センター, 研究員
|
|---|
| Project Period (FY) |
2004 – 2006
|
| Project Status |
Completed (Fiscal Year 2006)
|
| Budget Amount *help |
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2004: ¥5,100,000 (Direct Cost: ¥5,100,000)
|
|---|
| Keywords | harmonic generation / wavelength conversion / nonlinear optical crystal / pulse laser / repetitive irradiation / laser absorption / beam quality / electronics implementation / 高周波発生 |
|---|
| Research Abstract |
The wavelength conversion technology with nonlinear optical crystals is important for laser precision microfabrication. The conventional researches / developments about harmonic generation under repetitive irradiation have been conducted experimentally or empirically. Theoretical studies about them have dealt with single pulse irradiation or steady state under continuous irradiation. Phase matching that is indispensable for wavelength conversion is sensitive to the temperature of crystal, and conversion efficiency falls when its temperature is changed. The temperature of crystal is changed due to laser absorption. Therefore, it is impossible to analyze influence of the temperature change in the crystal on wavelength conversion by the conventional theoretical analysis.
In this research, the non-steady state theoretical analysis considering the influence of laser absorption under repetitive irradiation was performed. First, about second harmonic generation, the governing equations of the
… More
harmonics generation were derived by considering laser absorption, and a coupling analysis model with the heat conduction equation was constructed. KDP and KTP were supposed as nonlinear optical crystals. Promotion of high efficiency by the high intensity of incident pulse caused by the focusing effect was also analyzed. Based on the constructed model, optimum phase matching temperature was investigated. As a result, it was found that the high conversion efficiency is achieved by tuning phase matching temperature to the maximum temperature reached in the crystal. It was clarified also that the conversion efficiency is affected by the beam divergence angle and the repetition frequency. However, according to the proposed method, it was confirmed by simulations that high conversion efficiency is obtained without receiving influence of them.
Fundamental studies in electronics application, such as measurement of the temperature dependence of the absorption coefficient of silicon, the laser internal processing of silicon single crystal and thermohydrodynamics analysis of laser drilling by considering multiple reflection and evaporation were also performed. Less
|
