2pi ambiguity-free optical distance measurement with subnanometer precision with a novel phase-crossing low-coherence interferometer.

  title={2pi ambiguity-free optical distance measurement with subnanometer precision with a novel phase-crossing low-coherence interferometer.},
  author={Changhuei Yang and Adam Wax and Ramachandra R. Dasari and M. S. Feld},
  journal={Optics letters},
  volume={27 2},
We report a highly accurate phase-based technique for measuring arbitrarily long optical distance with subnanometer precision. The method employs a Michelson interferometer with a pair of harmonically related light sources, one cw and the other low coherence. By slightly detuning (~2 nm) the center wavelength of the low-coherence source between scans of the target sample, we can use the phase relationship between the heterodyne signals of the cw and the low-coherence light to measure the… 

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