One-dimensional And Two-dimensional Photonic Crystals' Optical Properties

The study on photonic crystal devices is an important research field,which could have broad application in the future,so it is paid more and more attentions by counterparts.By calculating the properties of photonic crystals to find the photonic crystal micro-structures that meets the requirements,this method is essential to manufacture the photonic crystals.For one-dimensional photonic crystals part,the characteristic transfer matrix method is used to research the relationship between the reflectivity and micro-structure of the layered photonic crystals,the influence on the reflection characteristics caused by oblique incidence,and the impact on the properties by changes of the defect parameters or types of the defect modes.And the plane wave expansion method is used to calculate the band structure of the infinite cycle one-dimensional photonic crystal and the defect modes.It can be found from the band structures of one-dimensional photonic crystals at different directions that the TE modes' band structure has different trend of changes with the TM modes' when the direction changes.When the transition angle changes from 0°to 45°,the widths of the first TE modes' bandgaps changes little,and there is just some movement of the bandgaps' position.Beside movement of the bandgap's position,the widths of the first TM modes' bandgaps significantly gradually decrease,and the first bandgap is completely disappeared especially at the 45°.Thus,there will be apparent polarization phenomenon in one-dimensional photonic crystals at this condition.This is consistent with the conclusion gotten by the characteristic transfer matrix method.For two-dimensional photonic crystals,the plane wave expansion method is used to research the relationship of the square and triangular structure between the band structure and the microstructure.And the influence on the band structures caused by oblique incidence also is studied by the whole vector formula.It can be found that: whether the square or triangular structure photonic crystals',although the band structures' shape of the TE modes is very similar to the TM modes',their positions of bandgap are different,especially the first TE mode bandgap of the square structure in <11> direction is completely staggered with the TM mode's.Along with the wave vector k's angle increases,the width of the first TE mode bandgap decreases and even vanish when the wave vector is in the(-1,0,1)plane,while the TM mode band structure curves become flat,the width of bandgap also increases at first,and then gradually decreases until disappear.