Frequency dependence of laser ultrasonic SAW phase velocities measurements

► We verified the relationship of phase velocity and frequency range of laser ultrasonics signal. ► We tested laser ultrasonics signal in hard and soft solid using low coherence interferometry. ► Increasing of phase velocity indicates the increase the frequency range. ► Increasing of the phase velocity indicates the increase of Young's modulus. ► Proper transducer for laser ultrasonics signal detection can be selected.