Optical visualization of ultrasonic pulses in the Total Internal Reflection Ultrasonic Sensor

An acousto-optic technique exploiting spatial filtration of light diffraction orders is used to visualize ultrasonic pulses in a TeO₂ crystal, which is an ultrasonic sensor body. In the experiments, images of a sought shear and a spurious longitudinal waves emitted by a shear wave transducer were recorded. An unexpected occurrence of a satellite ultrasonic pulse due to a mismatched size of the radiating transducer was observed. No conversion of a SH mode at its reflection from the oblique free surface of the crystal was observed. At the same time, an inexplicable displacement of an ultrasonic beam was discovered that might be a manifestation of the acoustic Goos-Hänchen effect.