Perfectly Absorbing Exceptional Points and Chiral Absorbers
Perfectly Absorbing Exceptional Points and Chiral Absorbers
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DOI：
10.1103/physrevlett.122.093901
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发表时间：
2019-03-05
影响因子：
8.6
通讯作者：
Stone, A. Douglas
中科院分区：
文献类型：
--
作者：
Sweeney, William R.;Hsu, Chia Wei;Stone, A. Douglas
我们确定了一种新的物理可实现的异常点（EP），对应于简并相干完美吸收，其中电磁波或声波的波算子的两个纯输入解合并为单一状态。与激光器中的 EP 相比，这种非厄米简并性可以在实值频率下发生，没有任何相关的噪声或非线性。 EP 附近本征通道的吸收线形状在任何维度上其最大值附近的频率都是四次方。一般来说，对于出现算子 EP 的参数，相关的散射矩阵没有 EP。然而，在一维中，当 S 矩阵确实具有完美吸收 EP 时，它呈现出一种通用的单参数形式，所有散射系数均具有简并值。对于吸收盘谐振器，这些 EP 会产生手性吸收：仅针对输入波的一种旋转方向的完美吸收。
We identify a new kind of physically realizable exceptional point (EP) corresponding to degenerate coherent perfect absorption, in which two purely incoming solutions of the wave operator for electromagnetic or acoustic waves coalesce to a single state. Such non-Hermitian degeneracies can occur at a real-valued frequency without any associated noise or nonlinearity, in contrast to EPs in lasers. The absorption line shape for the eigenchannel near the EP is quartic in frequency around its maximum in any dimension. In general, for the parameters at which an operator EP occurs, the associated scattering matrix does not have an EP. However, in one dimension, when the S matrix does have a perfectly absorbing EP, it takes on a universal one-parameter form with degenerate values for all scattering coefficients. For absorbing disk resonators, these EPs give rise to chiral absorption: perfect absorption for only one sense of rotation of the input wave.