Light Diffraction by Ultrasonic‐Wave Visualization

The time dependence of the intensity of light in the Fresnel region diffracted by a progressive wave was investigated recently by H. M. Colbert and K. L. Zankel. The present study considers the time dependence of such light at the plane of visualization of the ultrasonic wave. The theory is presented for visualizing periodic ultrasonic wave of arbitrary form when it can be considered as a phase object. Experimental and theoretical results are compared and the usefulness of visualization in determining the shape of the ultrasonic wave is considered. It is concluded that the method would be useful in determining the relative magnitudes of the Fourier components, as well as relative phases among the components that arise in a dispersive medium.