Periodic Microstructures Of Electromagnetic Wave Reflection And Transmission And Absorption Characteristics

Periodic structures which consist of dielectrics and metals possess two general features: interfaces and periodicity. Because of the interfaces, the structures may support many kinds of electromagnetic (EM) modes (bulk modes and interface modes such as guided modes and surface plasmon modes). Because of the periodictiy, the structures may be strongly anisotropic and be able to support and modulate different EM modes. Thus EM waves in these structures can show unusual propagating properties such as extraordinary transmission, abnormal refraction and so on. These interesting phenomena attract us to do further research. The thesis consists of four chapters.In Chapter One we briefly review the basic properties of photonic crystals and surface plasmon polaritons. By introducing them, we can understand some important concepts such as band structures, subwavelength and evanescent waves.In Chapter Two we introduce algorithms and simulation software used in our research, including the plane-wave method, finite-difference time-domain method (FDTD), transfer-matrix method and some basics of the RSoft Software.The main results of this thesis are given in Chapters Three to Five, which are about the propagating properties of EM waves in periodic structures. In Chapter three we discuss the transmission, reflection and absorption of flat metals, and in Chapter Four we discuss the transmission, reflection and absorption of 1D photonic crystals with extra periodic structures. We find the selective extraordinary transmission in these systems and discuss the underlying physics.In Chapter Five we discuss the abnormal refraction in periodic structures. Starting from the equal-frequency contour map, we catalog different negative refractive materials and design some structures that show positive and negative refractions simultaneously, imaging with negative reflection and zero-reflection. Then we analyze the relations between negative refraction and imaging beyond the diffraction limit. In the end we give a new idea of subwavelength imaging: effective infinite-index materials and compound-eye subwavelength imaging system.