Periodic And Quasi-periodic Lattice Wave Field And The Vortex

In recent years,the application of periodic microstructure in photonics has become a hot spot of research,which has attracted wide attention from researchers both at home and abroad.Photonic crystal lattice is a kind of artificial microstructure with periodic distribution of dielectric coefficient.As a new kind of optical material,the periodic band gap structure of photonic crystal provides a new way for people to control the propagation of light wave,which has broad application prospects in the field of optics.The traditional methods of fabricating photonic lattices are complex,expensive and difficult to produce in large area,while the new method is widely used because of its simplicity,convenience and low cost.This method is based on the photorefractive effect of optical media.The corresponding distribution of the refractive index of the nonlinear medium is induced by the periodic or quasi periodic distribution of the incident light field.The refractive index of the nonlinear medium is induced by the periodic or quasi periodic distribution of the incident light field.It is the precondition and foundation for further study to generate the periodic non diffracting wave field.At present,the common method is to make use of the multiple beam interference.Based on this principle,the method of mask and spatial light modulator is used to generate the lattice wave field and some valuable results have been obtained.The vortex lattice wave field is widely used in the study of the optical tweezers and the angular momentum of the particles.Therefore,it is a meaningful task to generate different modes of vortex lattice wave field.In this paper,the author discussed the periodic and quasi-periodic lattice wave field and the vortex structure.The main framework of this paper is as follows:1.The author briefly introduced the light induced method,the history and background of photonic crystals,and the significance of the research.2.Briefly introduced the basic theory involved in this paper,including the photorefractive effect and its physical mechanism,non diffracting beam and its basic types.Finally the author introduced the photonic lattice structure characteristics and listed two kinds of common experimental devices.3.The physical expression of discrete non diffracting wave field generated by multiple beam interference is derived.The author used matlab to simulate the two-dimensional six angle lattice generated by the coherence of the beam of six non diffracting beams with different phase modulation,and analyzed and compared the simulation results and drew some interesting conclusions.Having studied the transition intensity pattern on the formation of honeycomb photonic lattice distortion and honeycomb photonic lattices,then we find the most suitable phase modulation to generate distortion of honeycomb photonic lattices.Finally,the corresponding six dimensional lattice wave field has been simulated.4.The author compared the intensity of the 5 light beams and the interference of the 12 beams with the spiral phase modulation in the lattice wave field,analyzed the multiple symmetry of the structure and observed some vortex structures in the light field.We used the spatial light modulator to realize the multiple beam interference and measured the non-diffracting distance of some quasi periodic and periodic lattice wave fields.It was proved that the discrete diffraction free optical field generated in this method can be used to fabricate photonic lattices.5.The author used the computer simulation to obtain the periodic photonic lattice wave field,which is formed by two triangular,quadrangular,hexagonal photonic lattice light field superposition at a specific angle.We discussd the intensity spectra and phase diagrams obtained by superimposing the wave-fields of different size ratios,and analyze and summarize the structural characteristics of the new light field.