Study On The Propagation Characteristics Of Cu - Zn Alloy Film / Air Interface

The metal-based film structure is important for many optical materials applied in the optical field, and plays a significant role in modem optical instruments and optoelectronic materials. In the thesis, we described the interesting phenomena of negative refraction observed from metal-based materials with research progress in recent years. In order to understand the physical origin of the negative refraction in the metal-based artificial metamaterial, therefore, it is quite meaningful to study the light transmission with unique refraction phenomenon happened at the metal/dielectric interface in the nature.The research work was carried out by focusing mainly on the light transmission characteristics of optical thin film with the results given as below.1. A series of wedge-shaped alloy and metal thin film samples were fabricated by RF magnetron sputtering with the incident angles which were precisely controlled. Based on Snell’s law, the refraction of the light passing through the metal/air interface was quantitatively measured, and the relationship between incidence and refraction angles with the apparent refraction index was studied. The spectroscopic ellipsometer was used to measure the complex dielectric function and refraction index. The results show that the refraction for the Cu0.9Zn0.1and Cu0.7Zn0.3alloy samples in the visible region is negative, and will change from negative to positive as the photon energy increases. But the reflection is always positive for the pure Zn sample in the same photon energy region.2. In terms of the result which shows the refractive angles changing from negative to positive at different wavelengths and metal/air interface, we studied and discussed those possible mechanisms with controversial used to explain the physical origin of the negative refraction effect in past years, such as the plasma resonance effect, negative permeability effect and so on. Based on the detailed calculation and analysis, we believe that the light refraction in the visible band is mainly related to the changes of the group velocity and group index caused by the dispersion characters of metal in Drude region, but not with others.The results given in this work will stimulate people to understand more of the physical properties of the light transmission in the metal-based materials with expectation of their great application in the photonics material and device design in the future.