title: Doppler optical coherence microscopy for studies of cochlear mechanics.
abstract: The possibility of measuring subnanometer motions with micron scale spatial resolution in the intact mammalian cochlea using Doppler optical coherence microscopy (DOCM) is demonstrated. A novel DOCM system is described that uses two acousto-optic modulators to generate a stable 500-kHz heterodyne frequency. Images and motion measurements are obtained using phase-resolved analysis of the interference signal. The DOCM system permits imaging with micron-scale resolution and 85-dB sensitivity and motion measurements with 100-kHz bandwidth, directional discrimination, and 30-pm/Hz(0.5) noise floor. Images and motion measurements are presented that demonstrate the ability to resolve motions of structures of interest in a mammalian cochlea in vitro including the basilar membrane, reticular lamina, tectorial membrane, and outer hair cells.
authors.affiliation: Massachusetts Institute of Technology, Research Laboratory of Electronics, Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts 02139, USA.
authors.forename: Stanley S
authors.initials: SS
authors.lastname: Hong
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Freeman
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000295:instrumentation* / Q000379:methods; D003051:Cochlea / Q000033:anatomy & histology* / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005849:Gerbillinae; D066298:In Vitro Techniques; D033401:Microscopy, Acoustic / Q000295:instrumentation* / Q000379:methods; D009068:Movement / Q000502:physiology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods; D018608:Ultrasonography, Doppler / Q000295:instrumentation* / Q000379:methods