Confocal Acoustic Holography

This thesis summarizes work at the University of Victoria to design and evaluate a prototype instrument called the Confocal Acoustic Holography Microscope. The CAHM will be able to measure small changes in temperature and composition in a fluid specimen, which can be indirectly measured via small fluctuations in the speed of sound. The CAHM combines concepts of confocal microscopy, interferometry, and ultrasonic imaging. The design of the CAHM involved the production of a 3D CAD model and ray tracing simulations using Zemax optical design software. Simulated acoustic holograms and fringe shifts were produced, which were shown to match up well with theoretical calculations. A simplified acoustic holography instrument was also built and tested. The fringe spacing and phase shifts measured experimentally matched up well with the Zemax simulations and the theoretical calculations. To our knowledge, this is the first use of Zemax for acoustic designs. Based on the successful results of the simulations and experiments, the CAHM is expected to have many useful applications, especially in medical diagnostics where it could be used to measure density and temperature within the human body.