Sichtbarmuchung von stehenden Ultraschallfeldern und akustisch-optische Bildivandlung

After a survey of existing methods of exploring ultrasonic fields and the transposition of acoustic into optical images, new methods are described. In particular, the distortion of a liquid surface or the pressure changes within the liquid can be registered on gelatine or silver films. The photographic plate, usually insensitive to ultrasonics, can be made quite sensitive thereto by irradiating the developed silver films of a plate in a reversal bath. In this way it is possible under exposure times of the order of seconds, even in weak sound fields, to obtain practical acoustic-optical images.