A laser feedback interferometer with an oscillating feedback mirror

A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modulated accordingly. The modulation amplitude can be extracted using a phase sensitive...

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Bibliographic Details
Published inChinese physics B Vol. 21; no. 11; pp. 227 - 232
Main Author 汪之国 王飞 肖光宗
Format Journal Article
LanguageEnglish
Published 01.11.2012
Subjects
Discrimination
Feedback
Interferometers
Lasers
Modulation
Phase shift
Sine waves
Waveforms
偏振分束器
光强度调制
反射镜
干涉仪
振荡
方向辨别
激光反馈
移动方向
Online AccessGet full text
ISSN1674-1056
2058-3834
2058-3834
1741-4199
DOI10.1088/1674-1056/21/11/114201

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Summary:A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modulated accordingly. The modulation amplitude can be extracted using a phase sensitive detector （PSD）. When the feedback mirror moves, the PSD output shows a quasi-sine waveform similar to a laser intensity interference fringe but with a phase difference of approximately ±π/2. If the movement direction of the feedback mirror changes, the phase difference sign reverses. Therefore, the laser feedback interferometer offers a potential application in displacement measurement with a resolution of 1/8 wavelength and in-time direction discrimination. Without using optical components such as polarization beam splitters and wave plates, the interferometer is very simple, easy to align, and less costly.
Bibliography:He Ne laser, laser feedback interferometer, dithering
Wang Zhi-Guo, Wang Fei, and Xiao Guang-Zong Department of Optoelectronic Engineering, College of Optoelectronic Science and Engineering National University of Defense Technology, Changsha 410073, China
A method is proposed to solve the problem of direction discrimination for laser feedback interferometers. By vibrating the feedback mirror with a small-amplitude and high-frequency sine wave, laser intensity is modulated accordingly. The modulation amplitude can be extracted using a phase sensitive detector （PSD）. When the feedback mirror moves, the PSD output shows a quasi-sine waveform similar to a laser intensity interference fringe but with a phase difference of approximately ±π/2. If the movement direction of the feedback mirror changes, the phase difference sign reverses. Therefore, the laser feedback interferometer offers a potential application in displacement measurement with a resolution of 1/8 wavelength and in-time direction discrimination. Without using optical components such as polarization beam splitters and wave plates, the interferometer is very simple, easy to align, and less costly.
11-5639/O4
ObjectType-Article-1
SourceType-Scholarly Journals-1
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content type line 23
ISSN:1674-1056
2058-3834
2058-3834
1741-4199
DOI:10.1088/1674-1056/21/11/114201