Principles of Fluorescence

Specific biological and in the case of Quantum Dots inorganic materials have the capacity to absorb light of a particular wavelength, this energy excites electrons of a low energy state to a higher state, loss of energy is emitted as fluorescent light which can be detected be photomultiplier tubes in the case of flow cytometric instruments.

The sections below show these principles in diagrammatic form and descriptions of filters (put in front of detectors) and mirrors (change and split fluorescent light paths) normally found in flow cytometers.

Excitation and emission profiles

Stokes shift

Barrier filters

 

Dichroic mirrors