A Fluorescent microscope is a tool for the examination and study of microscopic specimens that absorb light and emit fluorescence. To obtain specific and meaningful fluorescence it is essential to stain the specimens with fluorescing dyes called fluorophores or fluorochromes. Using the fluorescent microscope is a highly sensitive method because very small quantities of a fluorophore can often be pictured with good microscopic contrast. Images that are brightly fluoresced can be examined against a dark background in most applications. For optimum fluorescence, the user of the fluorescent microscope must keep in mind some factors like the fact that individual fluorophores have different absorption and emission spectra, and also different quantum efficiency, which is the ratio between the energy absorbed and the energy emitted. In using fluorescent microscope, it is essential to illuminate the specimen with the light of a specific wavelength. This light is then absorbed and then emitted by the fluorophores in longer wavelengths of light that is of a separate color than the absorbed light. Through the use of an emission filter, the illumination light is separated from the much weaker emitted fluorescence. The usual components of a fluorescent microscope are the light source, which can either be Xenon or Mercury arc-discharge lamp, the excitation filter, the dichroic mirror, and the emission filter. The filters and the dichroic are chosen to match the spectral excitation and emission characteristics of the fluorophore used to label the specimen.

It is basic for a fluorescent microscope to have a light source essential to light up the specimen and the optics needed to watch the fluorescence. Aside from the light source and optics, filters must be utilized to isolate appropriate excitation and emission wavelengths. An excitation filter picks out a limited range of excitation wavelengths from the light source that corresponds to the absorption spectrum of the fluorochrome. Filters that separate emitted light from unabsorbed exciting light are called barrier filters. Final images by a fluorescent microscope can be observed by the eye, or it can be measured, photographed, and recorded by the usual means. Illumination used in a fluorescent microscope can be of two types: transmitted and incident. Transmitted illumination, the type the earliest fluorescence microscopes relied on, commonly uses a dark-ground condenser to aid in the division of fluorescent and exciting light. In incident illumination, light is directed down through the objective onto the specimen and then returned by reflection.

The modern fluorescent microscope merges the high performance optical components and the acquisition of digital image to result in a level that far exceeds that of simple observation by the human eye. The use of fluorescent microscope is now greatly dependent on rapidly acquiring information at low light levels or at visually undetectable wavelengths by the use electronic imaging. These technical enhancements are vital components of the fluorescent microscope as a system and not just mere “window dressing”.

The fluorescent microscopes are now primarily used in the field of medicine. It is used in the development of diagnostic tests wherein a red, green, or blue fluorescent dye has been attached to monoclonal antibodies. The different dyes expose various components in the specimen, such as macromolecules like deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) or bacteria, viruses, and other components.