fluorescence
Fluorescence
Fluorescence refers to the absorption of light and the subsequent emission of light that are two different frequencies or wavelengths. This typically occurs in an experimental setup where incident light of one low wavelength band is absorbed in one direction and light of another higher wavelength band is emitted in all directions. This is especially true when the sample absorbs ultraviolet light (invisible to the human eye) and emits visible light.
Sample molecules can be excited electrons, which vibrate due to the impact of incident photons, change to a lower vibrational state by heating the surrounding sample, and then the electrons return to the ground state, emitting photons of lower energy (higher wavelength) than the absorbed photons.
Fluorescence can be used to study some samples because fluorescent molecules absorb certain wavelengths of light and emit another. With the known wavelength of incident light, the composition of the sample can be identified based on the spectrum emitted by the sample. Because fluorescence occurs at the molecular level (typically one photon is incident and one is emitted), it is a spectroscopic technique that can identify single molecules. See also Fluorescence Measurement Techniques.
fluorescent coating
Fluorophore Coating
A phosphor coating is applied to the Detector to increase sensitivity in the ultraviolet range. This coating emits lower frequency photons that are recognized by the pixels at the ultraviolet end of the Detector. See UV Coating.
