一种可溶性聚对苯衍生物三阶非线性光学性能研究

Research on Third-Order Nonlinear Optical Properties of a Soluble Poly(Paraphenylene) Derivative

为了研究聚对苯衍生物的三阶非线性光学性能,采用三氯化铁法合成了一种对称己氧基取代聚对苯衍生物(DHO PPP),该聚合物具有良好的溶解性和成膜性.在紫外吸收光谱上,DHO PPP的三氯甲烷溶液和薄膜在波长为532 nm处具有很小的线性吸收.采用标准后向简并四波混频系统在532 nm下对该聚合物的三氯甲烷稀溶液的三阶非线性光学效应进行了研究,发现三阶非线性极化率以及非线性折射率随溶液质量浓度的增加而线性增加,而二阶分子超极化率稳定在1 78×10-30 esu附近.当质量浓度达到5 g/L时,三阶非线性极化率为6 31×10-11 esu,非线性折射率达到1 65×10-9 esu.研究结果表明,DHO PPP具有良好的三阶非线性光学性能.

In order to investigate the nonlinear optical properties of a soluble poly(paraphenylene) (PPP) derivatives, poly(2,5-dihexyloxy-1,4-phenylene) (DHO-PPP) which could readily be solution-processed into films was synthesized by oxidation coupling using iron chloride as catalyst. The solution and film of DHO-PPP show very small absorption values at 532 nm in UV-Vis absorption spectra. The four diluted chloroform solution samples of DHO-PPP were prepared and the third-order nonlinear optical properties were studied with the backward degenerate four-wave mixing at 532 nm. By using the relative measurement technique, the third-order nonlinear optical susceptibility and the nonlinear refractive index are linearly increased with increasing the concentration of the solution, while the hyperpolarizability of DHO-PPP remains a constant value of 1.78 × 10-30 esu. When the concentration of the solution reaches 5 g/L, the third-order nonlinear optical susceptibility and nonlinear refractive index of DHO-PPP are 6.3l × 10-11 esu and 1.65 × 10-9 esu, respectively, which implies that this polymer has good nonlinear optical properties.