The Application Of Electromagnetic Wave Radiation And Propagation In Magnetic Photonic Crystals

In recent years,the nonreciprocal research of photonic crystals(PC)has drawn increasing interest.When time-reversal symmetry of magnetic photonic crystals(MPC)is broken,the wave equation solution is possible to form a non-paired format.And if space-inversal symmetry broken is introduced,the band of MPC becomes non-symmetrical structure,then nonreciprocal optical phenomena would appear,which can be used to design the diode,isolators,splitters and so on.The important issues are how to build a non-reciprocal magnetic photonic crystal structure and how to apply it to the real environment.Exploring the method to change the photonic crystal symmetry is the crucial way to achieve non-reciprocity.What’s more,loss and miniaturization are shortcomings inherent in the magnetic material,which are also the unavoidable problems.On the basis of previous work,this paper study the directional radiation and slow light systems in magnetic photonic crystals by simulation and experiment.Then we explore the physical mechanism of the unidirectional phenomena in the self-biased magnetic photonic crystal waveguide,specifically include:1.Exploring the impact of the symmetry of the photonic crystal structure on the band edge.Modify unit cell symmetry by multiple methods,to achieve directional radiation beams from four to two beams,and then a single beam,and maintained a good half-power beam width and directivity factor.One-dimensional circumferential sweep experiments verify the performance of the directional radiation.The method of constituting the photonic crystal by the gyromagnetic material and ordinary dielectric material is proposed,which prompt the band edge to leave the boundaries of the Brillouin zone boundary and achieve deflection exit.Changing magnetic field and the azimuth of unit cell.We can achieve a two-dimensional directional scanning at fixed frequency,with scanning angle of 15.4°.2.Proposing a method to measure the slow light band of MPC one-way waveguide based on FFT algorithm.Experimental we measured the electric field distribution in the waveguide and achieved slow light of 0.0066c.Then we explored the influence of magnetic loss and dielectric loss of unit cell material on slow light,proposed the methods and guidelines of reducing the loss and improved the unit cell structure of the waveguide boundaries,which leads to slow light decay reducing,and a good performance of field locality,slow light band width and group velocity dispersion.3.Building self-bias magnetic photonic crystal waveguide by self-bias magnetic material.Two opposite one-way modes in adjacent frequency range are found.By two-dimensional field scanning,we confirmed those two one-way modes belong to edge states.Based on FFT algorithm,we calculated the band structure of this waveguide in 12GHz-15GHz,and confirmed the mechanism of one-way characteristic is chiral edge state(CES)which is analogous to quantum Hall effect(QHE)in electron system,and is insensitive to the scattering body on the guide.We provides the basis on building a simple physical model of self-biased magnetic material.