A technique is presented for measuring small displacements by observing the frequency of spectral modulation of white light in a Michelson interferometer. An experiment is described in which the step size of a stepper-motor-driven translation stage was measured by recording the spectrum of light output from an interferometer and performing a cross-correlation calculation with theoretical spectra. Measurements made using standard laboratory-quality optical equipment were accurate to within ~10 nm for a range of over 100 μm.
© 1989 Optical Society of America
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