Study Of Tunable One-dimensional Photonic Crystals Consisting Of TiO2and MgF2with Defect Layer LiNbO3

In1987Yablonovitch and John respectively showed that the materials whose dielectric constants distribute periodically can change the acts of photons which spread in, and call these materials Photonic crystals. Photonic crystals have a lot of new physical properties. It can be used in the production of high-performance optical devices which have new concept or can’t be produced previously.Photonic band structure is the major characteristics of photonic crystal. It displays as:certain frequency electromagnetic wave can not propagate in the specific direction of photonic crystal. Along this direction incidence to photonic crystal, rays will be reflected completely, and formed photonic band gap. Another main characteristic of photonic crystal is photon localization, if introducing a certain degree defects into photonic crystal, destroying the crystal’s original symmetry, very narrow frequency defect states might appear in the band-gap of photonic crystal, and photon according the defect states frequency can be limited in the defect position, however, other frequency photon still be forbidden in the band-gap. Although complete photonic crystal has complete band gap, people pay more attention to defective one in the practical application. Because band gap has ability to limit electromagnetic wave, and defects provide possibility to direct electromagnetic wave. This has very practical value in photonic system. Under normal circumstances, once the photonic crystal preparation completed, the defect mode position is determined, so the application of photonic crystals is very limitations. If the photonic crystal bands gap can control, namely the direction of propagation of electromagnetic waves changes with the change of the people opinions, it will be a major breakthrough in the field of photonic crystal research. Therefore, many researchers pay close attention to the tunable band gap photonic crystal structure models that become a focus and difficult points.This paper studies the bands optical properties of TiO2/MgF2multilayer one-dimensional photonic crystal structure in visible region with transfer matrix method. Inserting LiNbO3defect layer has an impact to find a single defect mode and double defect mode band gap, which can be used in the study of tunable band gaps. That conductor Ag adds on both sides of the electro-optic material LiNbO3, adjusting the applied electric field, can get one-dimensional photonic crystal tunable band gap model in visible region. When do some adjustment on unit cell parameters of this model, we can also realize the photonic crystal adjustable band gap model in infrared and ultraviolet region. This thesis completes the research of one dimensional TiO2/MgF2tunable band gap photonic crystal, and lays a theoretical foundation of the actual preparation for adjustable gap optics.