# 17-21-046

photon intensity

Ip; I

density of photon flux with respect to solid angle in a specified direction
.
where Φp is the photon flux emitted in the given direction, and Ω is the solid angle containing that direction

Note 1 to entry: The distribution of the photon intensities as a function of the direction of emission, e.g. given by the polar angles (ϑ, φ), is used to determine the photon flux, Φp, within a certain solid angle, Ω, of a source:
.

Note 2 to entry: The corresponding radiometric quantity is "radiant intensity". The corresponding photometric quantity is "luminous intensity".

Note 3 to entry: The photon intensity is expressed in second to the power minus one times steradian to the power minus one (s−1·sr−1).

Note 4 to entry: This entry was numbered 845-01-32 in IEC 60050-845:1987.

Note 5 to entry: This entry was numbered 17-928 in CIE S 017:2011.

Publication date: 2020-12