Microscopic simulations of high harmonic generation from semiconductors
Microscopic simulations of high harmonic generation from semiconductors
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DOI：
10.1117/12.2607447
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发表时间：
2022-03
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通讯作者：
Alexander Trautmann;R. Zuo;Guifang Wang;W. Hannes;Shidong Yang;Le Huu Thong;C. Ngo;J. Steiner;Marcelo Ciappina;M. Reichelt;H. T. Duc;Xiaohong Song;Weifeng Yang;T. Meier
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文献类型：
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作者：
Alexander Trautmann;R. Zuo;Guifang Wang;W. Hannes;Shidong Yang;Le Huu Thong;C. Ngo;J. Steiner;Marcelo Ciappina;M. Reichelt;H. T. Duc;Xiaohong Song;Weifeng Yang;T. Meier
半导体布洛赫方程为计算和分析半导体的光学和电子性质提供了一种非常通用的微观方法。在这里，我们专注于高谐波产生所产生的驱动晶体系统非常强大的光学和太赫兹脉冲。采用适当的规范可以使我们在长度规范下求解半导体布洛赫方程。长度计被证明是有利的，因为它收敛于比速度计更少数量的频带，并且，此外，能够在频带间和频带内贡献之间进行独特的区分。除了奇次谐波极化平行于入射场，我们的方法也描述偶次谐波起源于贝瑞曲率和极化垂直于入射场。接下来，我们证明了电子和空穴碰撞/复合动力学是主要负责的带间高次谐波产生的各向异性。我们的研究结果连接电子/空穴后向散射的货车霍韦奇异性和前向散射与临界线的能带结构，我们表明，这种动态可以控制适当设计的双色场。此外，我们认为激子效应内的两个波段的模型，并表明，它们可以强烈地增强高次谐波发射强度适当选择的入射脉冲。当奇次谐波对应于1 s激子的能量时，该谐波比非相互作用的电子和空穴的发射大几个数量级。
The semiconductor Bloch equations provide a very versatile and microscopic approach to compute and analyze optical and electronic properties of semiconductors. Here, we focus on high harmonic generation arising from the driving of crystalline systems with very strong optical and Terahertz pulses. Implementing a proper gauge allows us to solve the semiconductor Bloch equations in the length gauge. The length gauge turns out to be advantageous since it converges for a smaller number of bands than the velocity gauge and, in addition, enables a unique distinction between inter- and intraband contributions. Besides odd harmonics polarized parallel to the incoming field our approach also describes even harmonics which originate from the Berry curvature and are polarized perpendicular to the incident field. Next, we demonstrate that the electron and hole collision/recombination dynamics is mainly responsible for the anisotropy of the interband high harmonic generation. Our findings connect the electron/hole backward scattering to van Hove singularities and the forward scattering with critical lines in the band structure and we show that this dynamics can be controlled by properly designed two-color fields. Furthermore, we consider excitonic effects within a two-band model and show that they can strongly enhance the high harmonic emission intensity for suitably chosen incident pulses. When an odd-order harmonic corresponds to the energy of the 1s exciton this harmonic is several orders of magnitude larger than the emission from non-interacting electrons and holes.