11 November 2010 Optical FMCW interference: a new technology for optical metrology
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recently successfully introduced into optics. Optical FMCW interference naturally generates a dynamic signal, both the phase and frequency of which are relative to the optical path difference between the two interfering optical waves. Hence, optical FMCW interference not only can measure the relative change of optical path difference (or other related parameters) more accurately and easily, but also can measure the absolute value of optical path difference (or other related parameters). The phase measurement gives a resolution thousands of times higher than the frequency measurement. Particularly, since the signal of optical FMCW interference is a dynamic signal, to calibrate the fractional phase, distinguish the phase-shift direction and count the number of full periods is quite easy. Therefore, compared with traditional optical homodyne interference, optical FMCW interference can offer a higher accuracy and a longer measurement range. During the last few years, some important achievements in both the theory and application of optical FMCW interference have been made. Today, optical FMCW interference has become a well-defined new branch of physical optics. The investigation of optical FMCW interference not only extends our knowledge about the nature of light, but also offers a new advanced technology for optical metrology. Optical FMCW interference can be used to upgrade some existing optical instruments and to create the new-conceptual optical instruments. In this paper, I attempt to review the principle and applications of optical FMCW interference in metrology.
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Gang Zheng, Gang Zheng, } "Optical FMCW interference: a new technology for optical metrology", Proc. SPIE 7855, Optical Metrology and Inspection for Industrial Applications, 78550Q (11 November 2010); doi: 10.1117/12.871815; https://doi.org/10.1117/12.871815

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