One-way diffraction effects in photonic crystal gratings made of isotropic materials
One-way diffraction effects in photonic crystal gratings made of isotropic materials
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DOI：
10.1103/physrevb.80.155117
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发表时间：
2009-10-01
影响因子：
3.7
通讯作者：
Serebryannikov, Andriy E.
中科院分区：
文献类型：
--
作者：
Serebryannikov, Andriy E.
研究了具有不同周期的本征各向同性光子晶体光栅中的反常衍射效应，重点研究了其宽带单向传输特性。结果表明，80%以上的入射波能量可以单向传输，即，通过仅改变照明侧，在相反方向上具有零透射，而偏振总是保持线性。大多数但不是所有的相关衍射效应可以使用等容线（IFC）和波矢量图来预测，这些图考虑了由于波纹而可能出现的IFC形状相关的附加传输通道。三个主要制度，即，隔离以及双向和单向平移，可以根据前侧波纹是否影响由后侧界面界定的半空间中的远场，以及透射是否仅在来自界面之一的侧面的照明处消失来区分。根据波矢图的特征，给出了这些区域存在的条件并进行了讨论。在某些情况下，类似的制度可能与这些条件相矛盾。入射角以及光子晶体特征方向与相应非波纹结构界面之间的角度的变化允许多种可以实现单向传输的情况。单向性的一般条件是零衍射级不耦合到Floquet-Bloch波。
The anomalous diffraction effects arising in the intrinsically isotropic photonic crystal gratings with different periods of the front-side and back-side interfaces are studied with the emphasis put on wideband one-way transmission. It is demonstrated that more than 80 percent of the incident-wave energy can be transmitted unidirectionally, i.e., with zero transmission in the opposite direction, by changing side of illumination only, while polarization always remains linear. Most but not all of the related diffraction effects can be predicted using isofrequency contours (IFCs) and wave-vector diagrams, which take into account the IFC-shape-dependent additional transmission channels that can appear due to corrugations. Three main regimes, i.e., isolation and bidirectional and unidirectional translation, can be distinguished, depending on whether the front-side corrugations affect the far field in the half space bounded by the back-side interface, and whether transmission is vanishing only at illumination from the side of one of the interfaces. The conditions providing the existence of these regimes are given and discussed in terms of the features of wave-vector diagrams. In some cases, similar regimes can appear being in contradiction with these conditions. Variation in the angle of incidence and the angle between the characteristic directions of photonic crystal and the interfaces of the corresponding noncorrugated structure allows one extending variety of situations, in which unidirectional transmission can be realized. The general condition of unidirectionality is that the zero diffraction order is not coupled to a Floquet-Bloch wave.