Photonic Crystal Negative Refraction Phenomena Theory And Characteristics

Photonic crystal (PC) which is an artificial structure has a periodic arrangement of dielectric or metallic materials on a length scale of wavelength emerges in recent years . The photonic band gap and defects in the photonic crystals have been utilized to demonstrate ultra small lasers, ultra small waveguides and resonant type narrow band filters. At the same time, negative refraction of electromagnetic waves in left handed materials has become of interest recently because it is the foundation for a variety of novel phenomena. On the other hand, bulk photonic crystals exhibit unique light propagation phenomena arising from the anomalous dispersion, and applications based on these anomalous dispersion have also been illuminated, such as an ultra low group velocity, superprisms, negative refractive structures and self collimating structures. These may bring about important potential in several scientific and technical areas.In the present thesis, two areas have been researched, photonic crystal and negative refraction phenomena. The subject of this thesis is to investigate the negative refraction characteristics of photonic crystals, and to explore some possibleapplications.The background of the thesis is introduced in Chapter1. As the structure of a photonic crystal is complex, it is relatively hard to analyze photonic crystal in an explicit way. In Chapter2, we first introduce basic theory of photonic crystal and computational methods, among several theoretical methods proposed for photonic crystals. A new finite difference time domain (FDTD) method is used to calculate the band structures and investigate defect modes and guide modes in such photonic crystal. Form any applications of photonic crystals , it is essential to design structures with large band gaps. Then we study the influence of structure of photonic crystals to the photonic band gap and expect wide application perspectives of photonic crystals. In chapter 3, the interrelated definition of negative refraction material and beam's special propagation phenomena has been illuminated. Our research is emphasized in chapter 4. In chapter 4, the negative refraction phenomenon in two-dimension (2D) photonic crystals (PCs) is investigated with the band structure calculation and equal frequency surface (EFS) of PCs. The frequency range of negative refraction phenomenon is analyzed, the FDTD is used to simulate the propagation of light at the interface and inside of the photonic crystals. It is concluded that the negative refraction phenomenon in two-dimension photonic crystals is real observed in the specifical frequency range. Finally, the negative refraction phenomenon in the different medium materials and different crystal lattice structures in different frequencies and model is compared in detail, and a new spectroscope of quadrangle and hexagonal 2D triangular array photonic crystal is designed. As an application example of negative refraction in photonic crystals, we propose a novel scheme of polarization beam splitters.In conclusion, the work is devoted to developing new numerical methods, designing new structures with large absolute band gap and studying the negative refraction for photonic crystals.