A frequently used imaging technique is based on a confocal geometry, where the light from the focus in the sample is imaged (e.g. with a microscope objective) onto a pinhole, behind which the optical power is detected. This geometry suppresses the influence of light coming from other regions in the sample, e.g. from before or after the focus, because such light can not efficiently pass through the pinhole. In effect, mainly the depth resolution is improved. The confocal principle is emphasized in the term confocal laser scanning microscopy, and discussed in more detail in the article on fluorescence microscopy.
Instead of fluorescence, one may exploit acoustic effects of pulsed laser beams; the resulting method is called optoacoustic or photoacoustic microscopy.