Interaction of Short Pulses of Focused Ultrasound with Interfaces and Plane-Parallel Objects

Abstract

Short pulses of focused ultrasound are effective instrument for measuring local velocity values of bulk acoustic modes and for studying local elastic properties of solids (microacoustical technique). The probe beam is originally formed in a coupling fluid and penetrates in the solid body as convergent beams of longitudinal and transverse elastic waves. Primary and repeated reflections at the front and back object surfaces give rise a series of time-resolved echo signals. Measuring time intervals between echo pulses gives propagation times through the object for diverse modes of elastic waves and makes it possible to find values of sonic velocities and elastic moduli.