Characteristic Analysis Of Special Photonic Crystal And Its Application

Photonic crystal (PC) is an artificial crystal obtained by periodically arranging at least two different materials. At present,theories of PC have been relatively mature, and devices based on PC have also been proposed. However, there are still some researches on special PCs need to be further developed and perfected for their unique features and important application prospects which traditional PCs do not have.In this dissertation, three types of special PC with good application prospects: one-dimensional (1D) metal dielectric photonic crystal (MDPC) with disorder degree, magnetized plasma dielectric photonic crystal (PDPC) and two-dimensional (2D) rhombus lattice photonic crystal (RLPC) are investigated, respectively. According to the requirements of applications, PC filters in 140GHz band with holes punched in dielectric and metal columns in waveguide are studied, respectively. Finally, a metallic PC filter is fabricated and the experimental tests are carried out.The main achievements and innovations are as follows:(1)Introducing disorder degree into 1D MDPC is proposed, and the influences of disorder degree on 1D MDPC are studied. Results show that the photonic band gap (PBG) can be effectively broaden when an appropriate degree of disorder is selected, but excessive large disorder will enhance the discrete of photon localization, and the continuous PBG will be split into a series of small PBG The more numbers of periods, the larger PBG can be formed. The PBG decreases with the incident angle increasing for TM and TE polarization.(2) Properties of the transmission,dispersion and PBG of magnetized PDPC are studied comprehensively and thoroughly. Characteristics of the TE polarization are studied for 1D PDPC with external magnetic field and arbitrary angle incidence using transfer matrix method (TMM).Results show that the position and width of the PBG can be effectively controlled by adjusting the external magnetic field, and the PBG can be extended with the incident angle increasing. Linear eigen equations of 2D PDPC with external magnetic field are obtained using modified plane wave method (PWM). The finite difference time domain (FDTD) auxiliary equations for plasma with arbitrary external magnetic field are obtained. Characteristics of TE polarization with arbitrary wave vector are analyzed for 2D magnetized PDPC by using FDTD method. For TM polarization, the PBG is enlarged with the increasing of plasma density and dielectric constant of dielectric. For TE polarization, a local PBG and two flat bands are firstly found when external magnetic field exists. The upper frequencies of the high and low flat bands correspond to the right-hand and left-hand cutoff frequencies, respectively. With increasing of the external magnetic field, the local PBG and flats bands will shift, and there is an optimal value to make the local PBG largest. Omnidirectional PBG exists when the dielectric constant of dielectric is increased. For an arbitrary wave vector, the central frequency of PBG shifts upwords and the PBG becomes smaller when wave vector in the z-direction increases.(3) Properties of PBG and transmission for 2D RLPC with an arbitrary lattice angle are studied. Results show:For 2D RLPC composed of air holes in silicon, when the lattice angle is larger than 40°, the first PBG of TE polarization always exists, and an optimal PBG can be found by changing the filling factor of air holes. While for TM polarization, the first gap is very small. Considering TM polarization of a dielectric pillar RLPC with 70°lattice angle, it is found that frequency of defect mode decreases when the filling of point defect rod increases. For line defects, as is shown by the FDTD simulation, all the defect modes can be well confined along the line, which means RLPC has great application prospect in designing arbitrary angle waveguides.(4) According to the requirements of applications,PC filters with holes punched in dielectric and metal columns in waveguide are studied using HFSS software, and a metallic PC filter with central frequency of 142.5GHz and 3dB bandwidth of 5.83GHz is fabricated, which is tested at 75GHz～110GHz and 100GHz～150GHz, respectively. Experimental result is in agreement with that of simulation.