Picosecond dynamic of aqueous sodium-copper chlorophyllin solution: an excited state absorption study

Abstract

This work reports on the singlet excited-state absorption spectrum of sodium-copper chlorophyllin using three distinct methods of Z-Scan measurement: white-light continuum Z-Scan technique ranging from 470 to 780 nm, tunable Z-Scan technique with femtosecond pulses (490–700 nm) and 532 nm Z-Scan technique with 100 ps pulse width. A transition from reverse saturation absorption (RSA) to saturable absorption (SA) was observed at 570 nm, and at 532 nm RSA was tested showing potential application as optical limiting device. Pump-probe technique was used to measure lifetime of the first singlet excited state (22 ps) and no evidence of triplet conversion was observed.