Transmission Characteristics Of Two-dimensional Composite Photonic Crystal Research

Photonic crystals (PCs) are artificial materials with a periodic modulation of their dielectric constant. Important characteristics of PCs include the existence of photonic bandgaps, unusual dispersion relations for the propagating light and highly localized electromagnetic modes thereby supporting applications such as all-optical logical elements, high efficiency lasers fabrication and low-loss waveguides. Scientists predict that PCs will lead to a revolution in information technology in the future. PCs have attracted great interests for their compactness and potential applications in all-optical communication network. Therefore, the theoretical and applied study of PC has been one of the hottest topics in several areas such as physics, material science and optical electronics.In this thesis, the transmission characteristics of two-dimensional photonic crystal and photonic waveguide are studied by using the Finite Difference Time Domain method (FDTD). The contents are presented as following:1. The background and the main properties of PC are introduced systematically. The application and the fabricated methods are also discussed. The main contents are presented.2. The main theoretical research methods are explained. The methods contain transfer matrix method (TMM), plane wave expansion method (PWM) and FDTD. FDTD methods can analyze the distribution and transmission of electromagnetism in PCs dynamically and accurately, and provide the characteristics of light pulse's electric field in time domain and frequency domain, which is convenient for the design and analysis of photonic crystals.3. The transmission properties of the 2-Dimensional (2D) complex dielectric PCs are studied. By changing media of the composite layers of dielectric cylinders, the results show that the photonic band gap related to its effective dielectric constant. The composite dielectric cylinder photonic waveguide is also investigated. The results provide the theoretical basis for the design of 2D PCs.4. A new 2D hybrid PC structure is proposed. By using the method of FDTD, the optical transmission properties of 2D hybrid PCs are studied. The results show that the new structure not only maintain the primary band gap of the former structures but also produce a new band gap. Compared to the compound dielectric cylinder, the simple one has not produced a new band gap. Both increasing the width of medium plate and the radius of embedded concentric circle are in favor of the new band gap emerging. The theory has a wide prospect for the design of photonic devices.