The present study focuses on the investigation of the linear and nonlinear optical properties corresponding to electronic transitions in the vicinity of Level Anti-Crossing (LAC) points from a theoretical perspective. The system under consideration is an InAs conical quantum dot embedded in an infinite GaAs nanowire. The special configuration of the system leads to repeatedly LAC points in the energy spectrum of the system, three of which are considered here. The findings indicate a forward-backward shift in the energy location of the linear and non-linear Absorption Coefficient (AC) around the LAC. On the other hand, it is demonstrated that in this vicinity, AC for the transition to one of the crossing levels vanishes while that of the other maximizes. It is also found that, save for the lowest transition, the nonlinear component has essentially little share of the total AC, nearly for all incident photon energies, due to the limited and low values of the transition dipole moment.

中文翻译：

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InAs/GaAs锥形量子点纳米线能级反交叉附近光学性质的异常变化

本研究重点从理论角度研究与能级反交叉（LAC）点附近的电子跃迁相对应的线性和非线性光学特性。正在考虑的系统是嵌入无限 GaAs 纳米线中的 InAs 锥形量子点。系统的特殊配置导致系统能谱中出现重复的LAC点，这里考虑其中的三个。研究结果表明，LAC 周围线性和非线性吸收系数 (AC) 的能量位置存在前后移。另一方面，事实证明，在该附近，过渡到一个交叉水平的 AC 消失，而另一个交叉水平的 AC 则最大化。我们还发现，除了最低的跃迁之外，由于跃迁偶极矩的值有限且较低，几乎对于所有入射光子能量，非线性分量在总 AC 中所占的份额基本上很小。