A confocal microscope is a type of light microscope that uses a laser to successively scan multiple depths, known as z-planes, producing numerous two-dimensional, high-resolution images that a computer constructs into a three-dimensional model. Like fluorescence microscopes, they generally use fluorescent stains to increase contrast and resolution. By utilizing a confocal pinhole (a narrow aperture) to reject out-of-focus background light, confocal microscopes capture thin ($<1$ μm), unblurred optical sections. This capability makes them highly useful for examining thick, living specimens such as biofilms, which cannot be observed well using traditional light microscopy because slicing them to create thinner specimens might kill or disturb the microbial community. However, they still lack the resolution required for viewing extremely thick intact tissue samples.