Theoretical Studies On Optical Characteristics Of Metal-dielectric Micro-nano Structures

In recent years,research of light transmission,reflection and absorption in association with micro-nanostructure has gained increasing attention.In general,metals and dielectric materials have been frequently used for design and manufacturing of the micro-nano photonics devices.So that a common challenge in these micro-nano photonic devices is how to control the transmission or absorption or even polarization characteristics of light in a more precise way.Based on the above considerations,the present thesis work mainly focuses on designing three different kinds of micro-nanostructures so as to effectively control the light properties,to analyze the mechanism and to deepen research on the corresponding optical properties.The main contents are as follows:For the optical absorber,by considering the optical absorption characteristics of the electromagnetic resonance-enhanced metal-dielectric micro-nanostructures,we proposed two types of absorber: metal-dielectric microplate array absorber and metal-dielectric nanoring absorber.The main principle is based on the surface plasmon resonance,using the classical "metal-dielectric-metal" structure.We use the aluminum and silica as the metal and dielectric materials thereby to achieve the efficient absorption in the near-infrared range.In addition,we proved that the absorption effect is tunable,insensitive to TE or TM polarization and to incident angles over a wide range.Pertaining to the optical activity of the tunable linearly polarized light,we implement the birefringence without utilizing any birefringent material,as it is difficult to quantitatively control the birefringence with traditional materials.We designed a mico-nanostructure by which a right and left circularly polarized light could experience different phase retardations,thus leading to the optical activity.The double open-port ring structure was proposed,and the phase control could be proved theoretically and numerically.Moreover,the magnitude of the phase could be easily and accurately tuned by adjusting the parameter of the structure.