利用Z-扫描测试技术研究了低功率下Sb80 Bi20纳米薄膜的非线性光学特性，并利用椭圆偏振光谱仪测量了薄膜光学常数及椭偏参数。实验结果表明Sb80Bi20薄膜具有较大的饱和非线性光学吸收，非线性系数约为-0.018 m/W，而非线性折射率效应却不明显。Sb80Bi20纳米薄膜的超分辨效应主要在于具有大的非线性吸收系数。理论计算表明35 nm厚薄膜可使高斯光束半径缩小大约10%。因此Sb80Bi20薄膜有望用于近场超分辨结构。

A Z-scan system is employed to investigate optical nonlinearity of Bi20Sb80 thin films under low laser intensity. Optical constants and ellipsometric parameters are measured by spectroscopic ellipsometry. Experimental results indicate that Sb80Bi20 films show giant nonlinear saturated absorption. The nonlinear absorption coefficient is about -0.018 m/W. However, there is no appreciable nonlinear refraction effect in measurement. The giant nonlinear saturated absorption is dominant response for super-resolution effect. The calculation result indicates that the squeezed half width of Gaussian spot with about 10% can be achieved in Sb80Bi20 films with thickness of 35 nm. The Sb80Bi20 nanofilms are shown to be very promising for super-resolution applications.