Experimental Arrangement for Performing Spatial Filtering of a Wavefront

E In some technical applications, it is necessary to filter certain spatial frequency components of a wavefront. In this publication, the experimental setup for performing spatial filtering is visualized. It uses a converging lens, in whose focal plane an opaque obstacle is placed at the positions corresponding to the frequencies to be blocked, and transparent in the rest. Subsequently, a new lens with the same focal length as the first lens will be placed, so that the original wavefront with the filtered spatial frequencies is reproduced at its output. The pair of lenses is referred to as afocal, and the described operation is known as spatial filtering