Proceedings of the Korean Society of Precision Engineering Conference (한국정밀공학회:학술대회논문집)
- 1997.10a
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- Pages.214-219
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- 1997
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- 2005-8446(pISSN)
A High-Resolution Heterodyne Interferometer using Beat Frequency between Two-Axial Modes of a HeNe Laser
2-종 모드 레이저를 이용한 고분해능 헤터로다인 간섭계
Abstract
We propose a new scheme of high-resolution heterodyne interferometer that employs the two-axial mode He-Ne laser with an inter-mode beat frequency of 600-1000 MHz. An electronic RF-heterodyne circuit lowers the beat frequency down to 5 MHz, so that the phase change of the interferometer output is precisely measured with a displacement resolution of 0.1 nanometer without significant loss of dynamic bandwidth. A thermal control scheme is adopted to stabilize the cavity length with aims to suppress frequency drifts caused by the phenomena of frequency pulling and polarization anisotropy of the two-axial mode laser to a stability level of 2 parts in
Keywords