1990 Fiscal Year Final Research Report Summary
Ultra-Precision Machining and Surface Evaluation of Optical Flats for High Power Ultra-Violet Lasers
| Project/Area Number |
02650104
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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 Univ, Faculty of Engg., Prof., 工学部, 教授 (40029129)
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| Project Period (FY) |
1990
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| Keywords | Ultra-Precision Grinding / Float Polishing / Ultra-Violet Laser / Laser Fusion / Surface Roughness / Scanning Tunneling Microscope / Laser Damage / Exima Laser |
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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 examiner lasers and laser fusion program. This year's study was summarized as follows :
1) Clean rooms keeping both constant temperature and humidity have been established for the ultra-precision machining and measuring. Anti-vibration foundations also have set up for ultra-precision instruments.
2) A scanning tunneling microscope (STM) has been founded by a photographic instruments for a Nomarski interference microscope in order to show the correct place for measuring the micro-surface structure by STM. The STM has been calibrated by measuring the grating having 1000 grooves per mm. It has succeeded to measure Mn-Zn ferrite surfaces by STM without metal coating, though the measured material is not conductive.
3) Various optical glasses have been ground into very smooth surfaces better than optically-polished ones by a ultra-precision surface grinder having a glass-ceramic spindle of zero-thermal expansion. Laser damage thresholds of ground laser glass surfaces have been measured. It is cleared that the damage threshold depends upon the surface roughness and contamination of ground surfaces. Ground surfaces show the higher damage thresholds rather than optically-polished surfaces.
4) The float-polished laser glass shows the highest laser damage threshold of 30J/cm^2, which is double number rather than that of optically-polished surfaces.
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