Excitation of ultrasonic Rayleigh leaky waves at liquid-solid interface for general angle incidence

Experimental results are presented to demonstrate the existence of ultrasonic leaky wave radiation from liquid-solid interface. This leaky wave is generated by a finite ultrasonic beam incident at any angle (not only at Rayleigh angle) to a liquid-solid interface and observed at the Rayleigh angle both forward and backward. It is suggested that the phenomena occurring at the Rayleigh angle incidence and producing (1) a complex reflected field and (2) a backscattered field are just two special cases of this general phenomenon.