Femtosecond laser pulses for surface-profile metrology.

Opt Lett

Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Science Town, Daejeon 305-701, South Korea.

Published: October 2005

We discuss two ways to use femtosecond pulsed lasers as a new interferometric light source for enhanced precision surface-profile metrology. First, a train of ultrafast laser pulses yields repeated low temporal coherence, which allows unequal-path scanning interferometry, which is not feasible with white light, to be performed. Second, the high spatial coherence of femtosecond pulsed lasers enables large-sized optics to be tested in nonsymmetric configurations with relatively small-sized reference surfaces. These two advantages are verified experimentally with Fizeau and Twyman-Green type scanning interferometers.

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http://dx.doi.org/10.1364/ol.30.002650DOI Listing

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