Determination of the Phase of an Ultrasound Field Using Light Diffraction

摘要

During the last few years light-diffraction tomography has become of increasing interest in the investigation of ultrasonic fields [1, 2, 3], for the determination of the vibration behaviour of ultrasonic transducers [4, 5], and as a reference method for the calibration of hydrophones [3, 6]. The technique used so far was restricted to low sound pressure amplitudes and the low MHz-frequency range (Raman-Nath region). Beyond this region distinct problems may occur since the light in the diffraction orders is subject to an additional phase shift [7] which will strongly affect the measurement of the phase of the ultrasound field. In a recent paper [8] we reported on the extension of the light-diffraction tomography technique beyond the Raman-Nath region. In this context one crucial point was the determination of the phase of the sound field which could not be generally solved.