2007 Fiscal Year Final Research Report Summary
Displacement measuring interferometer with picometer resolution from frequency shift using meter definition
| Project/Area Number |
17360062
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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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| Research Field |
Production engineering/Processing studies
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| Research Institution | Nagaoka University of Technology |
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Principal Investigator |
AKETAGAWA Masato Nagaoka University of Technology, Mechanical Department, Associate Prof. (10231854)
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| Co-Investigator(Kenkyū-buntansha) |
YANAGI Kazuhisa Nagaoka University of Technology, Mechanical Department, Prof (80108216)
NAMERIKAWA Toru Kanazawa University, Graduate School of Natural Science and Technology, 准教授 (30262554)
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| Project Period (FY) |
2005 – 2007
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| Keywords | meter definition / picometer / interferometer / phase modulation / lock-in detection / null method / frequency / external cavity laser diode |
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| Research Abstract |
Meter definition shows the length can be determined from frequency through the speed of light. From the theory, we have developed a displacement measuring interferometer with picometer resolution from frequency shift.
We have developed a phase modulation homodyne interferometer using an electricaloptical-modulator (EOM) and external cavity laser diode (ECLD). In the PMHI, a phase of an incident light from the ECLD is modulated with an EOM and the output signal of a photodiode at the end of interferometer is demodulated with the modulation signal using a lock-in amplifier. From this configuration, it is possible to determine an optical path difference L of wavelength A integer N(mode number) with accuracy of 10 pm or less using the null-method, because the lock-in demodulation can transfer a dark fringe(in the case, L=λN) into a null-cross-point of the lock-in output signal. In the proposed instrument, a displacement of movable mirror can be converted to a frequency shift of the ECLD. The frequency shift of the ECLD is determined from a beat signal between the ECLD and a frequency stabilized He-Ne laser. Using the aid, following results are obtained.
(1) We have examined non-linear interpolation error of a commercial heterodyne interferometer using the proposed method. We clarified that the interpolation error has periodical error corresponding to the wavelength of the light source in the heterodyne interferometer.
(2) We have directly measured a free spectral range (FSR) for a optical path difference of the PMHI using two ECLDs, which are locked at adjacent null-cross-points.
(3) We have measured an air-refractive-index fluctuation from the frequency shift of the ECLD. In the case, the PMHI is made of ultra-low-thermal expansion ceramics. The measured air-refractive-index fluctuation is well coincided with the theoretical one with Ciddor's equation using a temperature, humidity, CO2 contents and air-pressure.
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[Presentation] Development of laser interferometer with picometer resolution using frequency tunable laser -4th report wide range measurement and control optimazation-2007
Author(s)
Yuta, Hoshino, Masashi, Ishige, Banh, Quoc, Tuan, Ken, Kobayashi, Masato, Aketagawa
Organizer
2007 Spring meeting of Japan Society for Precision Engineering
Place of Presentation
Asahikawa
Year and Date
2007-09-14
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Development of laser interferometer with picometer resolution using frequency tunable laser-The 5th report: Compensation of the displacement measurement due to the fluctuation of the air refractive index-2007
Author(s)
Banh, Quoc, Tuan, Yuta, Hoshino, Masashi, Ishige, Ken, Kobayashi, Masato, Aketagawa
Organizer
2007 Spring meeting of Japan Society for Precision Engineering
Place of Presentation
Kawasaki
Year and Date
2007-03-17
Description
「研究成果報告書概要(欧文)」より
