G PHYSICS
G01 MEASURING; TESTING
G01N INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
21/00 Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
G01N21/62 Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
G01N21/63 optically excited
G01N21/64 Fluorescence; Phosphorescence
G01N21/6408 with measurement of decay time, time resolved fluorescence