People - Graduate Students - Blake Sturtevant - SRCA Poster 2006
Measurement of Bulk Acoustic Wave Velocities Using the Pulse Echo Overlap Technique
The Pulse Echo Overlap (PEO) technique is utilized to determine the velocities of bulk acoustic waves (BAWs) in several materials for the extraction of acoustic wave (AW) material properties. Along an arbitrary crystalline direction, there exist up to three unique modes of BAW propagation: one longitudinal or compressional wave and two transverse or shear waves. By passing a BAW into a sample material and measuring the time taken for the wave to return (echo), the phase velocity of a particular acoustic mode in the sample can be determined given prior knowledge of the path length (twice the sample thickness). From the determined phase velocities, the elastic and piezoelectric properties of the material can be extracted. Once these properties are determined, the phase velocity in an arbitrary direction can be calculated. The knowledge of the propagation properties is fundamental for the design of sensors and frequency control devices which are ever-present in today's high tech world.
Quartz has been used in this work as a material on which to refine our technique since its acoustic properties have already been studied extensively. Measurements in agreement with published results permit the use of PEO with a high level of confidence to measure the properties of attractive new piezoelectric materials which are currently less well understood.
Quartz BAW velocities are repeatedly being measured in this work to within 1% of those predicted along the same orientations in the literature.
Blake T. Sturtevant
Thesis Advisors: Dr. Robert Lad (PHY) and Dr. Mauricio Pereira da Cunha (EE)
Back to Blake Sturtevant
