Enhanced Three-Photon Absorption by Symmetric Twisted Intramolecular Charge Transfer
GUO Fu-Quan1,2, YANG Jun3, ZHANG Qi-Jin2, MING Hai3
1Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
2Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026
3Department of Physics, University of Science and Technology of China, Hefei 230026
Enhanced Three-Photon Absorption by Symmetric Twisted Intramolecular Charge Transfer
GUO Fu-Quan1,2;YANG Jun3;ZHANG Qi-Jin2;MING Hai3
1Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
2Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026
3Department of Physics, University of Science and Technology of China, Hefei 230026
Abstract： We report on a novel organic chromophore with symmetric twisted intramolecular charge transfer (TICT) state on excitation. The properties of nonlinear transmission induced by three-photon absorption (3PA) are demonstrated pumped with nanosecond laser pulse. Large 3PA cross sections as high as the order of 10-74cm6s2 have been obtained for nanosecond and picosecond laser pulses at 1064nm from intensity-dependent transmission measurements. Similar two emissive behaviours from one-photon and three-photon excited fluorescence spectra indicate that the linear and nonlinear fluorescences share the same TICT relaxation process from the excited states. The intensity dependence of upconversion fluorescence on the incident intensity obeys the cubic law that characterizes the three-photon absorption.
2005, Vol. 22 
