Fano absorption spectrum with the complex spectral analysis
Fano absorption spectrum with the complex spectral analysis
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DOI：
10.1103/physreva.96.052511
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发表时间：
2017-11-30
影响因子：
2.9
通讯作者：
Tanaka, Satoshi
中科院分区：
文献类型：
--
作者：
Fukuta, Taku;Garmon, Savannah;Tanaka, Satoshi
提出了一种用复数光谱分析来理解Fano吸收光谱的方法。研究了半无限超晶格中杂质的吸收光谱。连续介质上的边界条件导致了一个具有强能量依赖性的自能函数，它增强了有效哈密顿量本征值问题的非线性，产生了几个非解析依赖于耦合常数的共振态。通过到这些离散共振态的直接跃迁，完美地再现了整个光谱特征。即使在单一的光学跃迁路径下，光谱也表现出不对称的Fano轮廓，该轮廓在向非解析共振态的跃迁中被增强。当我们提取共振态分量时，也可以很好地理解例外点附近的光谱变化。
An approach to understanding the Fano absorption spectrum is presented in terms of the complex spectral analysis. The absorption spectrum of an impurity embedded in semi-infinite superlattice is investigated. The boundary condition on the continuum results in a self-energy function with strong energy dependence which enhances the nonlinearity of the eigenvalue problem of the effective Hamiltonian, yielding several resonance states with a nonanalytic dependence on the coupling constants. The overall spectral features are perfectly reproduced by the direct transitions to these discrete resonance states. Even with a single optical transition path the spectrum exhibits the asymmetric Fano profile, which is enhanced for the transition to the nonanalytic resonance states. The spectral change around the exceptional point can also be well understood when we extract the resonant state component.