Design and implementation of a fiber optic doppler optical coherence microscopy system for cochlear imaging

Abstract

In this thesis, the design and implementation of a fiber optic Doppler optical coherence microscopy (FO-DOCM) system for cochlear imaging applications is presented. The use of a fiber optic design significantly reduces system size and complexity and the construction of a novel alignment and micropositioning apparatus increases ease of use for the researcher performing the imaging. To enable precise measurements of tissue motion, a time domain DOCM approach is used, utilizing an acousto-optic modulator (AOM) based optical heterodyne system to generate a stationary interference carrier frequency. By referencing this interference signal against the AOM drive signals, measurements of motions with magnitude on the order of 10 pm are shown to be possible. In addition to interferometrically measuring small amplitude motion, the FO-DOCM system is shown to be capable of imaging with a volumetric resolution of 10 x 9 x 9 pm. Demonstrative results of imaging cochlear tissue are presented by using the FO-DOCM system to image and measure motion in a guinea pig cochlea in vitro.