Fluorescent labels absorb light at a particular wavelength and re-emit it at a longer wavelength. This process is known as fluorescence. When a sample stained with a fluorescent label is exposed to light from an excitation source, the label absorbs the energy and transitions to an excited state. After a brief moment, it returns to its ground state, releasing the absorbed energy as visible light. This emitted light is captured by the microscope's detector to produce an image.
