Confocal Imaging

Legend:
1 - light source (laser)
2 - dichroic mirror
3 - objektiv
4 - sample
5 - pinhole
6 - detector

The big advantage of confocal microscopy is the possibility to collect light exclusively from a single plane. A pinhole sitting conjugated to the focal plane (i.e.confocal) keeps light from the detector that is reflected/emitted from others than the focal plane. The laser scanning microscope scans the sample sequentially point by point and line by line and assembles the pixel information to one image. By moving the focus plane single images (optical slices) can be put together to build up a three dimensional stack that can be digitally processed afterwards.