8-辛烷氧基金属酞菁的皮秒三阶光学非线性与光限幅特性

Third-order optical nonlinearities and optical limiting of octa-octyloxy metallo-phthalocyanine for ps pulses in toluene

应用Z 扫描技术在甲苯溶液中研究了三种 8 辛烷氧基金属酞菁 [(C8H1 7O) 8PcZn(PcZn) ,(C8H1 7O) 8PcNi (PcNi)和 (C8H1 7O) 8PcPb(PcPb) ]在 5 32nm对 35ps脉冲激光的三阶非线性吸收和折射特性 .用多能级模型拟合实验数据 ,得到三种酞菁的激发单重态吸收截面积σex分别为 2 7× 10 - 1 7cm2 (PcZn) ,8.2× 10 - 1 8cm2 (PcNi)和 3.4× 10 - 1 8cm2(PcPb) ,相应的非线性折射率n2 =- 7.9× 10 - 1 3 ,- 5 .5× 10 - 1 3 和 - 1.6× 10 - 1 2 esu ,三种酞菁都具有自散焦效应 .通过入射能流与透射能流的关系 ,研究了该类分子在甲苯溶液中在 5 32nm对 35ps脉冲激光的限幅特性 ,限幅机理是基于激发单重态的反饱和吸收 .在T T0 =0 .5时 ,分别测定出它们的限幅阈值为 6 0mJ cm2 (PcZn) ,80mJ cm2 (PcNi)和130mJ cm2 (PcPb) .当入射能流达到 5 0 0mJ cm2 时 ,相应的最高输出能流分别为 40 ,80和 15 0mJ cm2 ,其中锌和镍酞菁的输出能流远低于同样条件下C60 的输出能流 (140mJ cm2 ) .

The third-order nonlinear optical properties of the octa-octyloxy metallo-phthalocyanines (C8H(17)O)(8) PcZn (PcZn) (C(8)H(17)O)g PcNi (PeNi) and (C(8)H(17)O)(8) PcPb (PePb) were studied by Z-scan using 35 ps laser pulses at 532 run in toluene. The excited singlet absorption cross-sections sigma(ex) of 2.7x10(-17) cm(2) (PcZn) 8.2x10(-18) cm(2) (PcNi) and 3.4x10(-18) cm (PcPb) were obtained by the simulation of experimental data using a multi-level model and the corresponding nonlinear refractive index n(2)=-7.9x10(-13) esu I -5.5x10(-13) esu, and -1.6x10(-12) eSU were also obtained respectively. The optical-limiting performances of this kind of molecules at 532 nm for 35 ps pulses have been investigated, and the limiting mechanism is the reverse saturable absorption of excited singlet states. The limiting thresholds at T/T(0) = 0.5 were measured to be 60, 80 and 130 mJ/cm(2) for (PcZn), (PcNi) and (PePb) respectively. When the incident fluence reached 0.5 J/cm(2), the corresponding transmitted fluences were 40, 80 and 150 mJ/cm(2) for (PcZn), (PcNi) and (PePb) respectively, in which the transmitted fluences of PcZn and PcNi were much lower than that of C(60) (140 mJ/cm(2)) under the same condition. These data suggest that the octa-octyloxy metallo-phthalocyanines are a kind of promising optical limiting materials.