Optical Induction And Research Of Periodic And Quasiperiodic Photonic Microstructures In Iron-doped Lithium Niobate Crystal

In recent years, optical microstructures have become an attractive area ofresearch, holding strong promises for novel applications in photonics. Photoniclattices are periodic optical microstructures that are designed to affect the motion ofphotons in a similar way that periodicity of a semiconductor crystal affects the motionof electrons. It is highly concerned and proposed for many applications due to theircapability of controlling and manipulating the flow of light in all dimensions.Quasicrystals are materials that possess a long-range order or rotational symmetry, butlack the characteristic translational periodicity of crystals. They have higher pointgroup symmetry than ordinary periodic crystals. This high degree of symmetry affectsoptical properties of structures and allows much weaker direction-dependentproperties. Research shows quasiperiodic microstructures can possess photonicbandgaps in which electromagnetic wave propagation is forbidden and photonicquasicrystals are more favourable in achieving complete bandgaps. So it is more andmore popular in this field. The optical induction technique is a convenient way forfabrication of photonic microstructures.In this paper, we design periodic and quasiperiodic photonic microstructures andfabricate them in Iron-doped lithium niobate crystal by the optical induction technique.The following several aspects works were doing:1. Briefly introduces the development of light-induced method, photonic crystalsand photonic quasicrystals, as well as the research ideas of the paper. And give asimple introduction to the basic theories and concepts involved in this paper.2. We demonstrate experimentally the formation of three-dimensional opticallyinduced photonic lattices in Self-defocusing Iron-doped lithium niobate crystal by asingle amplitude mask with5holes. And we monitor the three-dimensional periodic index microstructures by plane-wave guidance, far field diffraction pattern and BZspectroscopy. In addition, we research light propagation of a low focused beam in thethree-dimensional photonic lattices and observe unique diffraction pattern. And thereis obvious significance for the research of fabrication of three-dimensionalmicrostructures and light propagation in the structures.3. We fabricate a two-dimensional octagonal tiling structure in LiNbO₃:Fephotorefractive crystal by a single amplitude mask with eight holes. And analyze thephotonic quasicrystal structure by plane wave guiding, Brillouinzone spectroscopyand far field diffraction pattern imaging. In addition, we get complex Penrose-tiledstructure with7-,8-,9-,10-,11-,12-,16-fold rotational symmetry and surprisingpattern （mixed honeycomb） chequered with translational honeycomb symmetry androtational honeycomb symmetry structure by designing the amplitude mask properly.4. We present a new method about fabricating photonic lattices. We designed anexperimental device that changes the interference of multiple beams into alternateexposure of multiple two beam interference. This method simplifies the beamconfiguration of the interference of multiple beams so we fabricate structure that havemore concise symmetry.