多枝[1,3,4]-噁二唑衍生物的双光子吸收和光功率限幅特性

Two-photon Absorption and Optical Power Limiting Properties of Multibranch 1,3,4-Oxadiazole Derivatives

采用非线性透过率法测定了多枝[1,3,4]-噁二唑衍生物的双光子吸收性质.测定了化合物的单光子荧光光谱和双光子荧光光谱,在800 nm波长的激光激发下,9-乙基-3,6-双{5-(4-叔丁基苯基)-[1,3,4]噁二唑-2-苯乙烯基}-咔唑(3)和三-{5-(4-叔丁基苯基)-[1,3,4]噁二唑-2-苯乙烯基-4-苯基}-胺(4)能够发出很强的蓝色和黄绿色双光子上转换荧光,荧光峰分别位于485和547 nm.这些多枝结构化合物的双光子吸收截面较大(数值超过104GM),并具有很强的光限幅效应.多枝分子中重复单元的推拉电子结构和协同效应有效地增强了分子的双光子吸收性质.

TPA properties of carbozole-core and triphenylamine-core multi-branched 1,3,4-oxadiazole derivatives were measured with nonlinear transmission method. Single-photon excited fluorescence and two-photon excited fluorescence of chromophores were experimentally studied. When pumped with 800 nm laser irradiation, 9 -ethyl-3,6 -his （ 2- t 4- [ 5 - （ 4-tert-butyl-phenyl ） - [ 1,3,4 ] oxadiazol-2-yl 1 -phenyl t-vinyl ） -carbazole （ 3 ） and tris [ 4-（ 2- { 4- [ 5- （ 4-tert-butyl-phenyl ）- [ 1,3,4 ] oxadiazol-2-yl ] -phenyl t -vinyl ） -phenyl ] -amine （ 4 ） show strong two-photon excited blue and yellow green fluorescence at 485 nm and 547 nm respectively. These multibranched chromophores showed a large TPA cross-section （ values of 〉 104 GM can be achieved） and strong optical power limiting properties. The cooperative enhancement of TPA in these multi-branched structures was observed. This enhancement is partly attributed to the electronic coupling between the branches. The electronic push-pull structures in the repeated unit and their cooperative effect increase the TPA properties of multibranched molecules.