Abstract
A reflection-type ultrasonic C-mode imaging system with an ultrasonic phase conjugator and a waveguide has been built, and images at 10 MHz have been obtained for metal samples with surface undulations. Surface or sub-surface elastic properties were visualized with a small influence of the surface roughness. The waveguide worked to enlarge the effective aperture of the phase conjugator, to smooth the incident-angle dependence of the phase conjugate reflectivity, and to improve the signal-to-noise ratio of the phase conjugate signals. Schlieren images of the ultrasonic fields in the system are also presented.