1 March 2001 High-sensitivity surface-profile measurements by heterodyne white-light interferometer
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Abstract
A tandem white-light interferometer has been developed, based on the heterodyne technique, for highly accurate and sensitive surface profiling of a three-dimensional (3-D) object. Two acousto-optic modulators (AOMs) and two spherical reflecting mirrors are used in a Michelson interferometer to provide the optical frequency shift for white light. By using this technique in the tandem interferometer, the profiles of mirrorlike and diffusing surfaces of 3-D objects are measured with heterodyne signals of 200 kHz. The optical path difference of the interferometer can be stabilized by simultaneously using coherent and incoherent light. The experimental results show a 27-fold improvement in the stability of the interferometer and the possibility of achieving high accuracy of several tens of nanometers.
© (2001) Society of Photo-Optical Instrumentation Engineers (SPIE)
Akiko Hirai, Hirokazu Matsumoto, "High-sensitivity surface-profile measurements by heterodyne white-light interferometer," Optical Engineering 40(3), (1 March 2001). https://doi.org/10.1117/1.1349216 . Submission:
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