Measurement of changes in optical path length and reflectivity with phase-shifting laser feedback interferometry

Ben Ovryn, James H. Andrews

Research output: Contribution to journalArticle

25 Scopus citations


The operating characteristics of a novel phase-shifting interferometer are presented. Interference arises by reflecting the light from a sample back into the cavity of a cw He–Ne laser. Changes in phase and fringe visibility are calculated from an overdetermined set of phase-shifted intensity measurements with the phase shifts being introduced with an electro-optic modulator. The interferometer is sensitive enough to measure displacements below 1 Hz with a rms error of approximately 1 nm from a sample that reflects only 3% of the 28 mW that is incident on its surface. The interferometer is applied to the determination of cantilever bending of a piezoelectric bimorph.

Original languageEnglish (US)
Pages (from-to)1959-1967
Number of pages9
JournalApplied Optics
Issue number10
Publication statusPublished - Apr 1 1999


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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