太赫兹缝隙衍射的严格求解方法

A new strict method for solving the gap diffraction of terahertz wave

基于严格电磁场理论和结构拓展思想,提出了太赫兹缝隙结构衍射的严格物理模型,得到了太赫兹缝隙衍射情形下入射、衍射和透射区域内电磁场基本模式的严格表达。数值计算表明太赫兹波在晶体(砷化镓)、非金属(FR-4)等材料缝隙的透射系数与太赫兹波频率的变化趋势大体相似,得出缝隙材料对太赫兹波的透射系数影响不明显;但是,缝隙的个数、材料的种类以及基底材料的厚度对太赫兹缝隙衍射最大透射系数的影响明显。本文方法也可用于研究太赫兹波亚波长区域内、微纳光学元件体内衍射传输等问题。

Based on the rigorous electromagnetic theory and the structure development equivalent medium theory, a strict physical model of the terahertz wave diffracted by the gap structure is proposed. The strict expression of the basic mode of the electromagnetic field in the diffraction and transmission regions of terahertz wave incident on any surface gap is obtained. Numerical calculations show that the changing trend of the THz wave propagating in the crystal（GaAs） is similar to that of its propagation in non-metal（FR-4）, and the material has not obvious effect on the transmission coefficient in the terahertz frequency. However, the number of gaps, the types of material and the thickness of the substrate material has obvious effect on the maximum transmission coefficient in the terahertz wave. The proposed method can also be used to study the TI-/z wave propagating in the sub-wavelength region, the diffraction and transmission of THz wave in micro-nano optical components and so on.