理论研究了由级联一维光子晶体构成的光子异质结构的全方位透射(反射)特性.其中各级联光子晶体的高低折射率介质相同、光学厚度比不同.以两个光子晶体级联的结构为对象,利用传输矩阵方法系统研究了不同偏振态光在不同入射角时光子帯隙的变化,得出实现全方位光子带隙的最大展宽条件,即前一光子晶体的帯隙上限要和后一光子晶体的带隙下限在最大入射角时重合.分别给出了满足和不满足该最大展宽条件的级联结构的全方位带隙参量,通过对全方位带隙宽度的比较说明了满足最大展宽条件的级联结构具有最大的全方位带隙宽度.

The omni-directional transmission (reflection) properties were theoretically investigated for photonic heterostructures composed of cascaded one-dimensional photonic crystals. Each photonic crystal in the structure has the same materials and different optical thickness ratios of the alternate high-and low-refractive index layers. Taking two photonic crystals cascaded structure as the object of study, the change of photonic bandgap with different polarization and incident angle was investigated through transfer matrix method, the condition of designing omnidirectional reflectors with the maximum photonic bandgap width was obtained, i.e., the upper bandgap edge of the former photonic crystal overlaps with the lower bandgap edge of the latter photonic crystal at the maximum incident angle. The parameters of the omnidirectional photonic bandgap were given for the cascaded structure with the condition satisfied and not satisfied. The widths of the omnidirectional photonic bandgap were compared. The results show that the cascaded structure with the condition satisfied has the maximum omnidirectional photonic bandgap width.