The angle dependency in FCPM
Assuming the transition dipole moments for absorption and emission
are parallel to the long axis of dye molecules and the excitation light
is linearly polarized, the absorbed light intensity is given by
Assuming further that the rotational relaxation time of the dye is slow compared to the lifetime
of the excited state, the orientation
of dye during re-emittance of light can be considered identical to the orientation
during absorption. The detectable light intensity is then given by
With follows
In consequence, the detectable light intensity scales with the angle between the excitation light and the transition dipole moment
over the relation