Investigation of Wavefront Fidelity of Phase Conjugate Waves by the Schlieren Method

Abstract

The fidelity of ultrasonic phase conjugate waves has been experimentally investigated at the wavefront level. Phase conjugate waves at 3.7 MHz were generated via nonlinear piezoelectricity of PZT (PbZrxTi1-xO3) ceramics, and wavefronts of the incident wave and the phase conjugate wave were visualized by the schlieren method. Wavefronts of an incident wave and those of the phase conjugate wave agreed with the errors of 1/6 the wavelength. A possible cause of the error is the diffraction effect due to the finite aperture of the phase conjugator. Some additional, noise-like ultrasonic fields were detected in schlieren images.