填充比对三角晶格等离子体光子晶体色散关系的影响

Effect of Filling Fraction on Dispersion Relations of Triangular Plasma Photonic Crystals

采用有限单元法,分别对TE模式、TM模式下三角晶格等离子体光子晶体的色散关系进行了理论计算,分析了等离子体填充比对能带位置和禁带宽度的影响。结果表明:TM模式下等离子体光子晶体在M-Γ、X-M两个方向上存在不完全带隙,随填充比的增加,带隙位置向高频移动,禁带宽度增大直至达到一稳定值。TE模式下等离子体光子晶体不仅存在禁带结构,还在低频处形成了表面等离子体波的平带结构。随填充比的增大,TE模式等离子体光子晶体由X-M单一方向的不完全带隙形成了完全带隙,带隙宽度随填充比的增大而增大。本文提供了一种可调谐等离子体光子晶体的有效方法,有望应用于微波、THz波的可调性控制。

The dispersion relations of the triangular plasma photonic crystals in TE mode and TM mode were calculated by finite element method.The influences of plasma filling fraction on the band positions and band gap widths were analyzed.The results show that the plasma photonic crystal has two unidirectional band gaps in M-Γand X-M directions,respectively in TM mode.With increasing of the filling fraction,the bands shift to higher frequencies,and the band gap widths increase and finally reach a stable value.In the TE mode,the plasma photonic crystal not only has a unidirectional band,but also has the flat bands with low frequencies,which are the surface plasma waves.A complete band gap forms at the large filling fraction,and the band gap widths increase with increasing of the filling fraction.An effective way for fabrication of tunable plasma photonic crystals is provided,which may find wide applications in the manipulation of microwaves or Terahertz waves.