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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.

Theory of fluorescence

Excitation and emission profiles

Stokes shift

Barrier filters

Dichroic mirrors

 

 

 
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by Gary Warnes. © Queen Mary, University of London 2007
Institute of Cell and Molecular Science, The Blizard Building, Barts and The London School of Medicine and Dentistry, 4 Newark Street, London E1 2AT, UK Tel: +44 (0)20 7882 2483, Fax: +44 (0)20 7882 2200