太赫兹(THz)光子晶体的研究在近些年得到快速发展,对其传输性质和相关功能器件的研究都有广泛报道,但现有研究很少从器件微加工和实验要求出发讨论器件的结构设计问题.通过数值模拟,明确了THz波段光子晶体基本几何参数的尺寸范围,重点分析了器件高度和传播方向上周期性单元个数对THz波传输性能的影响.研究结果表明,光子晶体的通带透过率随着光子晶体柱或孔高度增加而显著增加,保证柱或孔高度大于入射光波长是THz光子晶体加工中的一个重要要求;光子晶体沿传播方向行数越多,光子禁带内的透过率就越低,消光比越高,通带边沿就越陡峭,但通带的透过率会随着器件长度增加而下降,设计器件时需要折中考虑这两个因素的相互制约关系,确定最佳器件尺寸.研究结果为THz光子晶体的器件结构设计和微加工工艺设计提供理论指导.
Terahertz (THz) researches on photonic crystals (PhC) have a rapid development in recent years, which are widely reported on its transmission properties and related functional devices, but the present researches lack of the discussions on the structure design in the point view of the device fabrication and experi- ment. By numerical simulation, the basic geometry scale of THz PhC has been determined, mainly discussed the height dependence as well as the periodic unit number along the propagation direction on the THz transmission performance. The results show that the passband transmittances significantly increase with the PhC pillar or hole height increasing, so ensuring that the device height is greater than the incident wavelength is one of the important requirements in the fabrication of THz PhC~ The more PhC period number along the propagation di- rection, the lower the passband transmittances are, but the higher extinction ratio is, the more steep passband edges, so the device design requires a compromise of these two factors interaction to determine the optimum size of the device. Therefore, this research will provide a theoretical guidance for the structural design and micro fabrication of the THz PhC device.