Study On The Fabrication And Theoretical Analysis Of The Germanium Inverse Opal And Three Dimensional Ordered Arrays Of PLZT-SiO₂ Composites Photonic Crystal

Three photonic crystals(PCs), which have a complete photonic band gap(PBG) or an electro-induced PBG change effect, have attracted considerable attention in the recent years. In the thesis, photonic band structures of three dimensional PCs have been analyzed reasoned in theory. Germanium inverse opals against templates of colloidal crystals have been discussed, while some probing research have been done on the ordered arrays of PLZT-SiO2 Composites by synchronous-assembly approach.About the analysis of the photonic band structures following works have been carried out. Firstly, the PBG characters of 3D photonic crystals with different structures, including opal, dielectric-colloids composites (DCC), inverse opal(IO), simple diamond(SD) and woodpile, have been analysed by plane wave expansion method. Critical dielectric constantsεc have been got respectively through numeric simulation, and the results confirm that 3D PCs with SD structure has the smallestεc. The middle frequencyνm and a gap to mid-gap ratioΔof complete PBG of these PCs have been compared based on the same dielectric. In addition, because of the imperfect structures of IO PCs, which was that the filling fraction of the background dielectric medium inside the opal voids ff is less than 100% and the sintering factor sf which depends on the conglutination of the close-packed colloid spheres as template is more than 1, PBG will move to short-wavelength. The creationary frame of calculating the average filling factor ffev and the average sintering factor sfev has been presented based on the diversity of the middle frequencyνm of pseudo-gaps. At last, electro-induced photonic band gap change effect of 3D ferroelectrics inverse opal have been analysed,and it has been concluded that one pseudo-gap will disappear while another appear when electric intensity E changes.Ge IO PCs with periodic air-cores embedded inside the Germanium-shells have been prepared against templates of colloidal crystals through simple controllable filling techniques-chemical bath deposition (CBD). Influences of the precursor of germanium, concentration of the precursor solution and temperature on the filling condition have been searched, and the best technics of filling and calcinations has been ascertained. Besides, filling uniformity has been improved by centrifugal effect. And then reflect and transmission spectrums of the Ge-SiO2 composites and IO have been tested, while the differences between the test peak values and theoretical PBGs have been analysed.