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150 nm∶130 nm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3 nm.
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 u- sing the low-dielectric Fe304 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 permittivi- ty, the stop bands show redshifl 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 ( AA/A ) reaches 33.4% when the diameter ratio between core @ shell and core is 150 nm: 130 nm. 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 3 nm in the Fe3 04 @ TiO2 core @ shell structure.