Dynamic theory of nanophotonic control of two-dimensional semiconductor nonlinearities
Dynamic theory of nanophotonic control of two-dimensional semiconductor nonlinearities
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DOI：
10.1103/physrevb.98.245307
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发表时间：
2018-12
影响因子：
3.7
通讯作者：
S. Guazzotti;Andreas Pusch;D. Reiter;O. Hess
中科院分区：
文献类型：
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作者：
S. Guazzotti;Andreas Pusch;D. Reiter;O. Hess
我们介绍了一个麦克斯韦-布洛赫模拟方法，自洽地结合了微观描述的载流子和极化动力学的过渡金属-二硫属化物（TMDC）单层的时空全波时域模拟的麦克斯韦方程的基础上的时域有限差分法（FDTD）的方法超越缓慢变化的振幅或傍轴近似。这提供了一个平台，以现实的模型，特别是典型的超快光学激发实验中的微腔和纳米腔。我们的模拟证实，TMDC单层中库仑相互作用的弱屏蔽在线性光谱中产生了明显的激子线，并且我们发现了半导体麦克斯韦-布洛赫方程中由带内偶极矩表示的二阶非线性。这使我们能够计算TMDC单层的激子线周围的异常强大的二次谐波产生的光谱形状。我们证明，二次谐波信号可以显着地进一步增强了几个数量级，通过适当设计的（一维）光子微腔。由于其自洽性，灵活性，明确的时空分辨率在纳米尺度上，并准备访问光场和电子动力学，我们的理论和计算方法是一个理想的平台，设计和探索时空非线性和量子动力学在复杂的光子或等离子体微纳米结构的光电子，纳米光子和量子应用TMDC单层。
We introduce a Maxwell-Bloch simulation approach which self-consistently combines a microscopic description of the carrier and polarization dynamics of a transition-metal-dichalcogenide (TMDC) monolayer with a spatiotemporal full-wave time-domain simulation of Maxwell’s equations on the basis of a finite-difference time-domain (FDTD) method beyond the slowly varying amplitude or paraxial approximations. This offers a platform to realistically model, in particular, the typical ultrafast optical excitation experiments in microand nanocavities. Our simulations confirm that the weak screening of the Coulomb interaction in TMDC monolayers yields pronounced exciton lines in the linear spectrum and we uncover the second-order nonlinearity represented in the semiconductor Maxwell-Bloch equations by an intraband dipole moment. This allows us to calculate the spectral shape of the exceptionally strong second-harmonic generation around the exciton lines of TMDC monolayers. We demonstrate that the second-harmonic signal can remarkably be further enhanced by several orders of magnitude through a suitably designed (one-dimensional) photonic microcavity. Due to its self-consistency, flexibility, explicit spatio-temporal resolution on the nanoscale and the ready access to light field and electron dynamics, our theory and computational approach is an ideal platform to design and explore spatiotemporal nonlinear and quantum dynamics in complex photonic or plasmonic microand nanostructures for optoelectronic, nanophotonic and quantum applications of TMDC monolayers.