Multiple-time-scale dynamic studies of nonlinear transmission of pulsed lasers in a multiphoton-absorbing organic material

A dynamic model for the multiphoton interactions of an organic nonlinear absorber with pulsed lasers of various pulse durations spanning the femtosecond-to-microsecond time scale is presented. The formalism applies to all nonlinear absorbers with two-photon and singlet and triplet excited-state absorptions. Our quantitative analyses of experimental nonlinear transmission data and detailed exposition of the molecular dynamics have clearly illustrated the dynamic roles played by ground-and excited-states population saturation and depletion effects and their critical dependence on the laser intensity and temporal characteristics in governing the nonlinear transmission of pulsed lasers in such media.