
length, and f is the quantum efficiency, which reflects the fluorophore’s ability
to convert absorbed light into emitted fluorescence (i.e., the ratio of the number
of photons emitted to the number of photons absorbed). The level of intensity,
or brightness, of the emission produced by a fluorophore depends on its ability
to absorb light at a particular wavelength (i.e., its extinction coefficient, «) and
on the quantum efficiency. Typical values of « for fluorophores at their charac-
teristic absorption wavelength are in the range of tens of thousands, whereas the
f may range from 0 (no fluorescence) to 1 (100% efficiency). Fluorescence
intensity is also influenced ...