通过时域有限差分方法(FDTD)计算了核壳结构胶体光子晶体的光学传输特性.这一核壳结构是由低介电的Fe3O4核与高介电的TiO2壳构成的.计算结果表明, 阻带的行为受到材料介电常数和核壳比的调控.随着材料介电常数的增加, 阻带不断红移, 并且带宽不断增大.当核壳结构的整体尺寸一定时, 随着核直径的增大, 阻带不断蓝移, 并且在核壳结构直径与核直径之比为150nm∶130nm时, 带宽最大, 达到33.4%; 当核尺寸一定时, 随着核壳结构整体尺寸的增大, 阻带红移.在Fe3O4@TiO2核壳结构中, 能够出现阻带的TiO2壳层的最小厚度是3nm.

The optical transmission characteristic of colloidal photonic crystals with core @shell structure has been calculated via the finite-difference time-domain (FDTD) method. The core @shell structure has been designed using the low-dielectric Fe3O4 core and high-dielectric TiO2 shell. The results show that the behaviors of stop band can be adjusted by the effective permittivity and core @shell size ratio of materials. With the increase of permittivity, the stop bands show redshift and bandwidth increase. When the overall size of core @shell is constant, the stop bands show blueshift with the increasing core diameter, and the maximum bandwidth (Δλ/λ) reaches 33.4% when the diameter ratio between core @shell and core is 150nm: 130nm. When the core size is constant, the stop bands show redshift with the increase of the overall size of the core @shell structure. The minimum thickness of TiO2 shell that can make the stop bands appear is 3nm in the Fe3O4@TiO2 core @shell structure.