贵金属薄膜与介质相关的表面光学特性研究

THE MEDIUM RELATED SURFACE OPTICAL PROPERTIES OF NOBLE METAL FILMS

采用不同折射率的梯形棱镜作衬底，室温下用热蒸发或电子束蒸发的方法，在棱镜底面生长一系列金膜和银膜，使用椭圆偏振光谱方法分别测量了金属与空气界面及金属与衬底界面的介电函数谱．发现从金属－衬底界面处测到的薄膜介电函数谱不仅有别于金属－空气界面处测到的值，而且随衬底折射率的不同而改变．通过对这种现象进行分析，可解释为是由贵金属与相关介质接触时的内表面光学特性变化所引起，金属内表面的光学性质有别于体材料和膜材料的光学性质。

A series of Au and Ag films was deposited on the Dove prisms with different refractive indices. By this solid contacting configuration, it was found that the spectra of dielectric function measured at the metal substrate interface do change with the refractive index and differ from those measured at the metal air interface in both the Drude and interband transition regions. This phenomenon may be explained by the surface optical properties of the noble metals, which will strongly depend on the ambient. The reconstruction of the surface state related to the different medium may account for the effect that should be taken into consideration in the optical and magneto optical applications involving metallic multilayer film structure design.