| Project/Area Number |
01550106
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械工作
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| Research Institution | Chubu University |
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Principal Investigator |
NAMBA Yoshiharu Chubu University, Faculty of Engg., Prof., 工学部, 教授 (40029129)
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| Project Period (FY) |
1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Ultra-pricision Machining / Float polishing / Surface roughness / Ultra-precision Grinding / STM / Stylus surface roughness measurement / Optical surface roughness measurement |
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| Research Abstract |
The final objects of this study is to develop the flat optical components having high accuracy, high transparency or reflectivity, higher laser damage threshold and higher responsibility for high power lasers of ultra-violet in wavelength, in order to help the development of high power excimer lasers and laser fusion program. This year's study was performed in the following three parts; ultra-precision machining of optical materials, establishing the surface roughness measuring systems in high precision and measuring laser damage thresholds in machined surfaces.
1) The surface roughness of less than 5nm Rmax or 0.5nm rms was obtained on various glass surfaces ground by using the ultra-precision surface grinder and a SDI500-75-B diamond wheel. The CVD-SIC on SiC which seems to be one of the ideal material as mirrors for high power ultra-violet lasers have been polished by the float polishing. The steps at grain boundaries have been seen after float polishing because the CVD film was not
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deposited uniformly in crystallographic orientation. The surface roughness of 0.2nm rms was obtained in a grain of small size. The development of uniform CVD-SIC film on SiC will introduce the smooth optical surface as a mirror after float polishing. The fused silica as the material of transparency in ultra-violet wavelength was polished into 0.14nm rms by the float polishing.
2) Dr. Jean M. Bennett came and stayed in Chubu University to fix her stylus- type ultra-precision surface roughness measuring system which is the most sensitive stylus system in the world and its noise level is 0.05nm rms. New scanning tunneling microscope having a Nomarski interference microscope has been developed with Seiko electronic industry. Magnetron spattering apparatus was also developed with JOEL for measuring STM image on bigger-sized sample of 15OX15OX30 mm.
3) High power laser was irradiated on ground and optically polished LHG-8 laser glass samples for measuring laser damage thresholds. The damage threshold of 25J/cm was obtained on ground surface. This value is much higher than that on optically-polished surfaces. Less
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