Heterodyne interferometer for in-situ and in-vivo vibration measurements in the inner ear

R. Link; Edgar W. Fischer; E. Dalhoff; S. Heim; Hans J. Tiziani; Hans-Peter Zenner; Anthony W. Gummer

doi:10.1117/12.200904

1 February 1995 Heterodyne interferometer for in situ and in vivo vibration measurements in the inner ear

R. Link, Edgar W. Fischer, E. Dalhoff, S. Heim, Hans J. Tiziani, Hans-Peter Zenner, Anthony W. Gummer

Proceedings Volume 2329, Optical and Imaging Techniques in Biomedicine; (1995) https://doi.org/10.1117/12.200904
Event: International Symposium on Biomedical Optics Europe '94, 1994, Lille, France

Abstract

Investigation of the inner ear is still the subject of basic research. The concept of an active filtering process in the mechano-electrical transfer mechanism in the inner ear (cochlea) was introduced. In this paper an optical approach detecting microvibrations is discussed. A fiber optic heterodyne interferometer with a miniaturized sensorhead was built. The fibers ensure flexibility and easy handling of the interferometer whereas the miniaturized sensorhead allows a non-invasive approach to the organ of Corti. In heterodyne interferometry as compared to classical interferometry two slightly different light frequencies for the reference and object beams are used. The vibration of the object is detected as a modulation of the phase of the detector signal. To obtain the information on the vibration two methods were analyzed and applied: namely measuring the amplitude of the sidebands in the spectrum of the modulated signal and secondly signal demodulation. It is possible to detect amplitudes down to 0.3 angstrom in a frequency range of 500 Hz to 50 kHz with a simulated object reflectivity of 0.02%.

Citation Download Citation

R. Link, Edgar W. Fischer, E. Dalhoff, S. Heim, Hans J. Tiziani, Hans-Peter Zenner, and Anthony W. Gummer "Heterodyne interferometer for in situ and in vivo vibration measurements in the inner ear", Proc. SPIE 2329, Optical and Imaging Techniques in Biomedicine, (1 February 1995); https://doi.org/10.1117/12.200904

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