Bright T J, Liu X L, Zhang Z M
Opt Express. 2014 Jun 30;22 Suppl 4:A1112-27. doi: 10.1364/OE.22.0A1112.
Metallodielectric photonic crystals having hyperbolic dispersions are called indefinite materials because of their ability to guide modes with extremely large lateral wavevectors. While this is useful for enhancing near-field radiative heat transfer, it could also give rise to large lateral displacements of the energy pathways. The energy streamlines can be used to depict the flow of electromagnetic energy through a structure when wave propagation does not follow ray optics. We obtain the energy streamlines through two semi-infinite uniaxial anisotropic effective medium structures, separated by a small vacuum gap, using the Green functions and fluctuation-dissipation theorem. The lateral shifts are determined from the streamlines within two penetration depths. For hyperbolic modes, the predicted lateral shift can be several thousand times of the vacuum gap width.
具有双曲线色散的金属介质光子晶体因其能够引导具有极大横向波矢的模式而被称为不定材料。虽然这对于增强近场辐射热传递很有用，但它也可能导致能量路径产生较大的横向位移。当波传播不遵循射线光学时，能量流线可用于描绘电磁能量通过结构的流动。我们使用格林函数和涨落耗散定理，通过两个由小真空间隙隔开的半无限单轴各向异性有效介质结构来获得能量流线。横向位移由两个穿透深度内的流线确定。对于双曲线模式，预测的横向位移可能是真空间隙宽度的数千倍。
