Recording depth of the heterodyne laser interferometer for cochlear vibration measurement

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Measurement of the cochlear partition vibration as a function of the optical-axis (z-axis) position in the gerbil cochlea showed that the velocity distributes over a range of more than 300 μm, which is larger than the thickness of the cochlear partition. This finding suggests that the recording depth (RD) of the heterodyne interferometer probably is not as small as reported in the literature. In the current experiment, the RD of the heterodyne laser interferometer was studied by measuring the velocity of a vibrating mirror as a function of the z-axis position. Results demonstrate that the optical sectioning characteristic, measured by the intensity of the reflected laser beam as a function of the z-axis position, is not able to correctly estimate the RD of the heterodyne intefferometer: the RD is much larger than optical sectioning, indicating a poor spatial resolution along the z axis.

Original languageEnglish (US)
Pages (from-to)826-829
Number of pages4
JournalJournal of the Acoustical Society of America
Issue number2
StatePublished - Feb 21 2001


ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics

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