Anomalous reflection and transmission of surface acoustic waves at a crystal edge via coupling to leaky wedge waves

Surface acoustic waves are propagated toward the edge of an anisotropic elastic medium (a silicon crystal), which supports leaky waves with a high degree of localization at the tip of the edge. At an angle of incidence corresponding to phase matching with this leaky wedge wave, a sharp peak in the reflection coefficient of the surface wave was found. This anomalous reflection is associated with efficient excitation of the leaky wedge wave. In laser ultrasound experiments, surface acoustic wave pulses were excited and their reflection from the edge of the sample and their partial conversion into leaky wedge wave pulses was observed by optical probe-beam deflection. The reflection scenario and the pulse shapes of the surface and wedge-localized guided waves, including the evolution of the acoustic pulse traveling along the edge, have been confirmed in detail by numerical simulations. Published under an exclusive license by AIP Publishing.

Automated summary

The study revealed the presence of highly localized leaky waves at the edge of a silicon crystal, with efficient excitation achieved at specific angles. The reflection of surface acoustic wave pulses from the sample edge and their partial conversion into leaky waves were observed using optical probe-beam deflection in laser ultrasound experiments.