Working Principle of Confocal Scanning Microscopes

Confocal scanning microscopy, after its invention and patent by M. L. Minsky in the 1950s and later with the novelty of employing lasers as the source, has lent itself to widespread use. By using a spatial pinhole to block the light scattered or reflected from out-of-focus planes, it helps improve the longitudinal resolution and contrast. In this example, we build a confocal scanning microscope in VirtualLab Fusion, and use a metallic grating with alternating ridges and grooves as the test object to demonstrate its working principle.