Two-frequency laser measuring technique with high axis velocity

Fengzhou Fang; Bryan Kok Ann Ngoi

doi:10.1117/12.323356

29 September 1998 Two-frequency laser measuring technique with high axis velocity

Fengzhou Fang, Bryan Kok Ann Ngoi

Proceedings Volume 3407, International Conference on Applied Optical Metrology; (1998) https://doi.org/10.1117/12.323356
Event: International Conference on Applied Optical Metrology, 1998, Balatonfured, Hungary

Abstract

Interferometers using heterodyne techniques are now widely employed for displacement measurements. Heterodyne interferometric techniques involve the use of two beams derived from the same laser, one of which has its frequency shifted by a specified amount. A helium-neon laser is forced to oscillate simultaneously at two frequencies separated by a constant difference of about 2 MHz, by applying an axial magnetic field. But the axis-velocity with this method is not able to be increased for a small frequency difference. An effective way of introducing such a frequency shift is by means of an acousto-optic modulator. It is studied in detail after a few methods are discussed for increasing the frequency difference. The measuring system will be used widely in displacement, objective with high speed motion of 1.8 m/s and on-line measurement.

Citation Download Citation

Fengzhou Fang and Bryan Kok Ann Ngoi "Two-frequency laser measuring technique with high axis velocity", Proc. SPIE 3407, International Conference on Applied Optical Metrology, (29 September 1998); https://doi.org/10.1117/12.323356

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