Definitions for "Spatial filter"
A spatial filter enables a laser beam to be filtered such that noise around the beam is reduced. A beam with a spatial filter will appear "cleaner", with less imperfections. The spatial filter consists of a focusing lens and a pinhole placed at the focus point of that lens. The beam goes through the lens, gets focused at the pinhole, and the parts of the beam that have diverged from the focus point due to imperfections in the lens or contamination will not go through the pinhole. Optical noise around the beam is thus filtered out. Lasiris Spatial Filters
A filter that operates in the spatial domain as opposed to the frequency domain to accentuate or attenuates the appearance of the spatial details, for example the transitions of intensity in an image.
a device which improves the spatial coherence of a laser beam by effectively removing the background noise, i