Study Of The Optical Properties Of Metal Matrix Thin-film Structures

This work mainly focuses on the study of optical properties of noble-metal-based thin films and metal oxide(Zinc Oxide) thin films.In the thesis,we describe the interesting phenomena of negative refraction observed for metal-based artificial materials with research progress in recent years.To explore the better and deeper understanding of negative refraction happened in these materials,we need to simplify the structure being studied.In this work,we intensively investigate the light transmission properties measured at the pure metal/air interface in the visible region.In terms of Snell's law,we have fabricated a series of wedged-shaped noble metal film samples(Au,Ag and Cu) with different incident angles using RF sputtering deposition method.In experiment,we chose four laser sources with the wavelength of 473 nm,532 nm,632.8 nm and 780 nm,respectively.On the basis of optical magnification principle,we quantitatively measured the refraction of the light passing through the metal/air interface,which is dependent on the incident angle and wavelength,and observed that the light refraction can change from negative to positive in the visible range at the simplest natural metal/air interface.The mechanisms to cause the negative refraction have been carefully discussed and analyzed,and are not attributed to the effects,such as the plasmon resonance,the negative permeability,the Goos-H(a|¨)nchen shift,and so on.Studies of metal oxides attract much attention in recent years,especially in the cutting-edge research on Zinc Oxide(ZnO).As the direct-band semiconductor material with wide bandgap,ZnO has exceptional photoelectric characteristics and will have the potential consequently to be put into wide application in the future. Spectroscopic ellipsometry is a non-destructive and non-contacting tool to characterize the optical properties of the photonics materials,which has been widely used in industry and academic research.We give the brief introduction of the principle of spectroscopic ellipsometry with general steps to do data analysis.In terms of different dispersion models and Effect Medium Approximation Method,we carefully studied the optical properties of ZnO thin films grown by ECR-PLD(electron cyclotron resonance plasma assisted pulsed laser deposition).We draw the conclusion that the proper data analysis model should be considered and applied to study the optical properties of ZnO films with different micro-structures. We hope the results given in this work will stimulate people to understand more of the physical properties of the light transmission in the metal-based artificial materials,and to know more of optical properties of ZnO thin film with different micro structures with expectation of their great application in the photonics material and device design and fabrication.