Abstract

Although interferometry is an essential tool for measuring distances or phase differences on the order of a wavelength or less, it is hampered in its applicability by a limited measurement range. This range is typically limited to λ/2 where λ is the center wavelength of the illumination source. There are many applications such as profilometry, displacement measurement and wavefront sensing, where measurements must be made over a range of many wavelengths. In these cases, the interferometer output must be processed in order to obtain the required range. However, the required processing is generally time consuming, precluding real-time measurements. We propose a new technique which allows real-time, unambiguous measurement over a range of many wavelengths.

© 1985 Optical Society of America