Experimental Study of Fraunhofer Light Diffraction by Ultrasonic Beams of Moderately High Frequency at Oblique Incidence

A systematic investigation of Fraunhofer light diffraction by a progressive ultrasonic wave is described. Measured light‐intensity distributions are compared with theoretical values obtained from numerical solution of the difference equations describing light diffraction and with the solutions of Phariseau for high ultrasonic frequencies. A criterion for Bragg‐type diffraction is established.