rate of photon number per time interval
Note 1 to entry: Photon flux,
Note 2 to entry: For a beam of radiation whose spectral distribution is or , the photon flux can be expressed by , where
Note 3 to entry: The corresponding radiometric quantity is "radiant flux". The corresponding photometric quantity is "luminous flux".
Note 4 to entry: The photon flux is expressed in second to the power minus one (s−1).
Note 5 to entry: This entry was numbered 845-01-26 in IEC 60050-845:1987.
Note 6 to entry: This entry was numbered 17-927 in CIE S 017:2011.