为了将单壁碳纳米管制成实际可用的光电子器件, 采用一种新的梯度升温热亚胺化法来制备单壁碳纳米管/聚酰亚胺薄膜。利用分光光度计测得单壁碳纳米管的质量分数为0.02的单壁碳纳米管/聚酰亚胺薄膜的反射谱、透射谱和吸收谱, 得到薄膜线性折射率随波长的变化;拟合Sellmeyer公式, 得到单壁碳纳米管/聚酰亚胺薄膜的Sellmeyer参量。利用z扫描技术研究了单壁碳纳米管/聚酰亚胺薄膜的3阶非线性特性。结果表明, 单壁碳纳米管/聚酰亚胺薄膜具有很强的饱和吸收特性, 其非线性吸收系数为β=-5.3×10-10 cm/W; 并且具有较强的自散焦效应, 对应的非线性折射系数为γ=-4.1×10-13 cm2/W。单壁碳纳米管/聚酰亚胺薄膜具有较强的非线性光学特性。

In order to prepare actual optoelectronic devices using single-walled carbon nanotubes, single-walled carbon nanotube/polyimide (SWCNT/PI) film with the single-walled carbon nanotubes in mass fraction of 0.02 was prepared by means of a new gradient temperature-elevating thermal imidization method. The reflectance, transmittance, and absorbance of the film were measured with a spectrophotometer and the linear refractive index variation with wavelength of SWCNT/PI film was obtained. Simultaneously, the Sellmeyer parameters of the SWCNT/PI film were got by fitting the Sellmeyer formula. Then, the third order nonlinear optical property of the SWCNT/PI film was studied by means of z-scanning. The experiments showed that the nonlinear absorption coefficient and the nonlinear refractive coefficient of the film were -5.3×10-9cm/W and -4.1×10-13cm2/W, respectively. The results prove that SWCNT/PI film owns strong nonlinear optical property.