| Original Articles |
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Laser Feedback Technique for Precise Retardation Measurements |
| FEI Li-Gang;ZHANG Shu-Lian |
| The State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084 |
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| Cite this article: |
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FEI Li-Gang, ZHANG Shu-Lian 2006 Chin. Phys. Lett. 23 2974-2977 |
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Abstract A simple and precise retardation measurement based on laser feedback is demonstrated. The measurement principle is based on polarization flipping induced by optical feedback from an external birefringence cavity. The measured wave plate is located in the external cavity. When the length of the external cavity is tuned, the polarization states of laser will flip between two eigenstates, and the position of polarization flipping in one period of intensity modulation will vary with retardation of the wave plate. The duty ratio of two eigenstates is used to determine the retardation. Main advantages of the technique are that it is compact, low cost, fast and flexible. Especially, it is insensitive to a fluctuation of laser intensity and is suitable for on-line measurement. The experimental results have shown that the measurement uncertainty is better than 0.03° in the range 30°--150°
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| Keywords:
42.60.By
42.25.Ja
42.25.Lc
42.62.Eh
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Published: 01 November 2006
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| PACS: |
42.60.By
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(Design of specific laser systems)
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42.25.Ja
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(Polarization)
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42.25.Lc
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(Birefringence)
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42.62.Eh
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(Metrological applications; optical frequency synthesizers for precision spectroscopy)
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