Long Xin, Bao Yuwen, Yuan Hongxia, Zhang Huayue, Dai Xiaoyu, Li Zhongfu, Jiang Leyong, Xiang Yuanjiang
Opt Express. 2022 Jun 6;30(12):20847-20858. doi: 10.1364/OE.460386.
The special band structure of three-dimensional Dirac semimetal (3D DSM) makes it show strong nonlinear optical characteristics in the terahertz region, which provides a new way to develop terahertz nonlinear devices with low threshold. In this paper, we theoretically study the optical bistability (OB) of transmitted light in a multilayer structure with 3D DSM embedded in two one-dimensional photonic crystals (1D PhC). The topological edge state (TES) excited by the 1D PhC heterostructure significantly enhances the local electric field near the nonlinear 3D DSM, which provides a positive condition for the realization of low threshold OB. Through parameter optimization, we obtain a threshold electric field with an incident electric field of 10 V/m levels. Furthermore, the influences of the Fermi energy and thickness of 3D DSM and the angle of the incident light on the hysteretic behavior as well as the threshold of OB are clarified. 3D DSM-based optical devices with intrinsic OB provide a building block for future integrated optical and all-optical networks.
三维狄拉克半金属（3D DSM）的特殊能带结构使其在太赫兹区域表现出很强的非线性光学特性，这为开发低阈值太赫兹非线性器件提供了一种新途径。本文中，我们从理论上研究了嵌入两个一维光子晶体（1D PhC）中的具有3D DSM的多层结构中透射光的光学双稳性（OB）。由1D PhC异质结构激发的拓扑边缘态（TES）显著增强了非线性3D DSM附近的局部电场，这为实现低阈值OB提供了有利条件。通过参数优化，我们获得了入射电场为10 V/m量级的阈值电场。此外，还阐明了3D DSM的费米能、厚度以及入射光角度对滞后行为和OB阈值的影响。基于3D DSM的具有固有OB的光学器件为未来的集成光学和全光网络提供了一个构建模块。
