Phenomenon Of Negative Refraction In Photonic Crystals With Magneto-optical Multilayer Isolators

Photonic Crystals (PC) is a kind of materials with periodic refractive indices such as dielectric, semiconductor or metal materials. The concept of photonic crystal was proposed at the end of 1980s. In recent ten years, it has become a new important research field due to its unique properties and many potential applications. As the structure of a photonic crystal is complex, it is relatively hard to analyze a photonic crystal by an analyzable method. People can only do so by numerical simulations. Therefore, many numerical simulations methods were devised. Using these methods, people investigate the theory of photonic crystal more and more.It is a new field for the study of left-hand materials and negative refraction. The left-hand materials possess a number of unusual electromagnetic effects. In particular, the discovery of negative refraction in photonic crystal has shown people a new research field of photonic crystal.In this dissertation, using finite difference time domain (FDTD) and plane-wave expansion method, we investigate the far-field focusing properties of two dimensional photonic crystals with rod-type honeycomb lattice. Furthermore, we present a new type magneto-optical multiplayer film isolator structure with multi-defect, using the one -dimensional photonic crystals theory.The main research works and conclusions are as following:1. The far-field focusing properties of two-dimensional photonic crystals with rod-type honeycomb lattice are investigated using finite difference time domain and plane-wave expansion method. The results match the wave-beam negative refraction law with relative refractive index of -1. But, the image qualities are limited by low transmission at large incident angle, they are improved by modifying the radius of rod near the surface of photonic crystals slab.2. It is important to study the effect caused by the defects in photonic crystal. We study the influence of the defect on the focusing and imaging in a two -dimensional photonic crystal flat lens. It is found that, for the far-field focusing, the defects near the surface of photonic crystal slab have an important effect on the coupling coefficients and image qualities. On the other hand, for the near-field focusing, we find that image can appear in a different direction when a line-defect was introduced. Furthermore, usingmulti-defect, we can control the number of images.3. To deal with the asymmetry of outer applied static magnetic field on MO multiplayer films isolator, we derivate a two dimensional transfer matrix method from real-space method for photonic band structure computations, and develop it to the calculation of transmission and reflection coefficients for anisotropic media.4. Using transfer matrix method, we investigated the influence of permittivity error on the properties of magneto-optical multi-layer isolator with single defect, and presented a new type multiplayer structure with multi-defect. Comparing with single defect structure, the bandwidth of Faraday rotation frequency response of multi-defect structure was increased greatly, and the tolerance of permittivity was increased by one order. Furthermore, the multi-defect structure has better tolerance of film thickness and incidence angle.