A correction factor for experimental multiphoton absorption cross section

Abstract

The experimental absorption cross section δ n of an n-photon process induced by pulsed laser radiation is shown to be dependent in a simple way on the distribution of the laser intensity. A gaussian radial distribution of the intensity leads to a correction factor of n −1 and a gaussain temporal distribution of the intensity within the pulse leads to a correction factor of n − 1 2 . Values for δ n derived from fluorescence intensity data without taking into account spatial and temporal intensity distributions should therefore be multiplied by a correction factor n 3 2 .