偶氮分散红聚合物薄膜的Z扫描研究

The Z-Scan Study of Azo Disperse Red Polymer Film

采用单光束Z扫描技术对新型光学存储材料偶氮分散红聚合物的薄膜样品进行了测量。实验结果表明 ,该样品的非线性折射率为负值。为消除非线性吸收的影响 ,将实验所得有孔Z扫描曲线除以开孔Z扫描曲线进行了处理。从Z扫描曲线的实验数据处理得到这种新型偶氮分散红聚合物薄膜材料的非线性折射率为 :- 5 .5× 10 -6cm2 /W ,其值比常见无机非线性光学材料大 8～ 9个数量级 ,是一种很有应用前景的新型光学存储材料。最后 ,对这种偶氮聚合物薄膜具有大的非线性折射率的物理机制进行了分析。初步认为 :在线偏振光照射下 ,偶氮分子变为各向异性。这些类似液晶相的分子很好地关联在一起 ,分子的取向对外界扰动的响应是一种集体的效果 ,所以他们具有很大的非线性响应。

A new type of optical storing material, the film sample of azobenzene disperse red polymer is measured by using the single beam Z-scan technique. The experimental results show that the nonlinear refractive index of the sample is a negative value. For eliminating the influence of nonlinear absorption, the Z-scan curve with an aperture is treated with the Z-scan curve without the aperture. The nonlinear refractive index of this type of azo polymer film is determinated as -5.5×10 -6 cm2/W according to the experimental data of Z-scan curve. The value of azo polymer film is larger 8～9 scales than the common inorganic materials. This material will have a very good prospect in the application of optical storage. The reason of large nonlinear refractive index in this material is discussed. Through pilot study, under the irradiation of linear polarized beam, azo molecules became anisotropic. These molecules just like liquid crystal are relevant each other well, response of molecular orientation to outside irritation is a collective effect, therefore they have very large nonlinear response.