共价键相联的卟啉-酞菁激发态性质——(Ⅱ)非线性光学性质研究

INVESTIGATION ON THE EXCITED STATE PROCESSES IN COVALENT-LINKED TETRATOLYLPORPHYRIN-PHTHALOCYANINE Ⅱ .NONLINEAR OPTICAL EFFECTS IN BINARY MOLECULES

卟啉(TTP)和酞菁(Pc)分子表现出反饱和吸收特性,而在卟啉和酞菁二元分子TTP-O-Pc和TTP-O-(CH_2)_s-O-Pc中反饱和吸收现象消失。简并四波混频(DFWM)方法用于测量兰阶非线性光学极化率X(3),二元分子比单元分子的X(3)提高了10~2倍以上,达到3×10^(-9)esu。

A technique of the degenerate four-wave mixing (DFWM) has been employed to study the nonlinear optical effects in binary molecules of TTP-O-Pc and TTP-O-(CH2)5-O-Pc. The third-order nonlinear susceptibility of x(3)in TTP-O-PC is increased by over two orders of magnitude compared with TTP and PC. With the increase of covalence length between TTP and PC from -O- to -O-(CH2)5-O-, x(3) of the latter is 3×10-9 esu that is 5 times of that of the former. The enhancement of the optical nonlinearity for binary molecules is attributed to the charge transfer. The inverse saturation absorption which is found in TTP and PC disappears in TTP-O-Pc and TTP-O(CH2)5-O-Pc owing to the ultra-fast transfer of intramolecular charge.