Whitman R L
Appl Opt. 1970 Jun 1;9(6):1375-8. doi: 10.1364/AO.9.001375.
This paper discusses an interference technique that makes it possible to directly observe and record the usually very weak light diffracted by an acoustical surface perturbation. This is accomplished by using spatial filtering techniques in combination with a frequency shifted reference beam. It is shown that the acoustically diffracted light may be visualized even in the presence of statically scattered light of much higher intensity. An experiment is described in which this technique is used to view the surface perturbations of piezoelectric ceramic material caused by acoustic surface waves. The application of this system to acoustic holography is discussed in detail. This application makes use of the fact that bulk acoustic waves in a material, upon striking the surface at some acute angle, cause surface ripple patterns which form a dynamic hologram of the acoustic field. A photographic image of this hologram frozen in time may then be recorded using the process discussed above.
本文讨论了一种干涉技术，该技术能够直接观察和记录通常由声学表面扰动衍射的非常微弱的光。这是通过将空间滤波技术与频移参考光束相结合来实现的。结果表明，即使存在强度高得多的静态散射光，声学衍射光也可以可视化。文中描述了一个实验，其中使用该技术来观察由声表面波引起的压电陶瓷材料的表面扰动。详细讨论了该系统在声全息术中的应用。该应用利用了这样一个事实，即材料中的体声波以一定锐角撞击表面时，会产生表面波纹图案，这些图案形成了声场的动态全息图。然后可以使用上述过程记录这个及时冻结的全息图的照片图像。
