Nonlinear absorption and excited state dynamics of porphyrin and phthalocyanine in the presence of explosive molecules

Abstract

Nonlinear absorption (NLA) properties and excited state dynamics of a porphyrin and phthalocyanine in the presence of explosive molecules were investigated using the nanosecond Z-scan and femtosecond pump-probe techniques, respectively. The NLA coefficients Is and β increased in the presence of explosive molecules. The change in first excited state decay time was evaluated through degenerate pump-probe measurements near 700 nm and it was observed that decay time decreased in the presence of explosive molecules. The reduction in decay time and increase in NLA coefficients varied with different molecules according to their absorption, emission properties and affinity towards the explosive molecule.