Ultrasonic Schlieren System Using a Pulsed Gas Laser

A pulsed gas laser emitting an extremely short duration and high power pulse at fast repetition rates has been used in an ultrasonic schlieren system. The system allows visualization of individual wavefronts within tone bursts of ultrasound at frequencies up to 20 MHz. Highly damped, high resolution pulses can also be imaged. The effect of vari- ations of the light pulse duration, jitter, and focal plane ap- erture on the resulting image is discussed. The experimental ultrasonic and optical systems are described, and examples of ultrasonic propagation are shown.