The fluorescence microscopes can observe a sample via specific labeling with fluorochromes. Only the signal from the fluorescent molecules is detected, thereby locating and observing the path of a given constituent in a sample.

A fluorochrome or fluorescent molecule has the property of emitting light at a well defined wavelength (color) when excited under specific conditions.

Proceeds to a fluorochrome excited state when it absorbs light energy at a wavelength (denoted λ) of its own (excitation light). It returns to the ground state very quickly by emitting light at a wavelength longer than that of excitation (emission light) wavelength.


The upright fluorescent microscopes are different from the optical microscope by the presence of a more powerful light source and filters for selecting a range of specific wavelength to excite the fluorochrome.

The light emitted in response to excitation by the sample is filtered to the emission wavelength of fluorochrome to only detect these molecules.

Observed in a sample fluorescence is rarely natural, most often, the molecules or structures of interest must be labeled with a fluorochrome. There are multiple fluorochromes each with a range of excitation and emission wavelength different. It is often possible to specifically label the item you wish to follow up with a fluorochrome. In addition, the diversity of fluorescent molecules can be observed simultaneously in the same sample, different and therefore different marker molecules. For example in a biological cell, the fluorochromes used to specifically label the nucleus, the actin network, different proteins, specific antibodies, intracellular compartments …

In addition, there are many techniques derived from fluorescence microscopy allows to follow the location of items marked in time and learn about their interactions with other elements.


Fluorescence microscope is used to locate a number of different molecules and optionally simultaneously to follow their path. Unlike the confocal microscope, the fluorescence microscope detects fluorochromes through the entire thickness of the sample. It can also be used for studies of materials and surfaces.