In fluorescence microscopy, the
sample you want to study is itself the light source.
The technique is used to study specimens, which can
be made to fluoresce. The fluorescence microscope is
based on the phenomenon that certain material emits
energy detectable as visible light when irradiated
with the light of a specific wavelength. The sample
can either be fluorescing in its natural form like
chlorophyll and some minerals, or treated with
The Sample Gets
The basic task of the
fluorescence microscope is to let excitation light
radiate the specimen and then sort out the much
weaker emitted light to make up the image. First, the
microscope has a filter that only lets through
radiation with the desired wavelength that matches
your fluorescing material. The radiation collides
with the atoms in your specimen and electrons are
excited to a higher energy level. When they relax to
a lower level, they emit light.
To become visible, the emitted
light is separated from the much brighter excitation
light in a second filter. Here, the fact that the
emitted light is of lower energy and has a longer
wavelength is used. The fluorescing areas can be
observed in the microscope and shine out against a
dark background with high contrast.
microscopy is a rapid expanding technique, both in
the medical and biological sciences. The technique
has made it possible to identify cells and cellular
components with a high degree of specificity. For
example, certain antibodies and disease conditions or
impurities in inorganic material can be studied with
the fluorescence microscopy.
1. Energy is
absorbed by the atom which becomes
2. The electron jumps to a higher energy
3. Soon, the electron drops back to the ground
state, emitting a photon (or a packet of light)
- the atom is fluorescing.