Mollow triplet emission and high-harmonic generation involving isolated impurity atoms of semiconductors in a strong terahertz field

强太赫兹场中涉及半导体孤立杂质原子的莫洛三重态发射和高次谐波产生

• 批准号: 390200638
• 负责人: Dr. Fanqi Meng
• 金额: --
• 依托单位: Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/390200638?language=en
• 关键词: Mollow; triplet; emission; harmonic; generation

This proposal asks for funding for a short research visit at the University of California at Santa Barbara (UCSB) in order to perform atomic-physics-type experiments on isolated dopant atoms in semiconductors with the university's free-electron laser (FEL). The proposal's two topics are the Mollow triplets-the frequency analogue of Rabi oscillations in a strong quasi-continuous terahertz field, and the generation of higher harmonics by charge carriers which, after ionization, are accelerated in the oscillating field and recollide with the dopant ions. These topics are strongly motivated by analog phenomena of atomic physics with gasses, where notably the observation of higher harmonics by the recollision phenomenon represents the foundation for the hot research field of attosecond physics. The embedding of isolated atoms in a host crystal has the consequence that nonlinear optical effects (with rather long coherence times) occur at much lower field strength and photon energy than in free atoms. Such phenomena could hardly be studied in the past for a lack of suitable radiation sources and measurement techniques. Building on our prior studies, we intend to take advantage of the UCSB-FEL's unique properties for the observation of the effects addressed above. These properties are the very small bandwidth of the FEL's long THz pulses which are favorable for the addressing of individual quantum states and the observation of newly generated sidebands, and the low radiation frequencies accessible (down to a few hundred GHz) which support the generation of high orders of the harmonics upon carrier-ion recollision.

该提案要求资助在加州大学圣巴巴拉分校 (UCSB) 进行短期研究访问，以便利用该大学的自由电子激光器 (FEL) 对半导体中的孤立掺杂原子进行原子物理类型的实验。该提案的两个主题是莫洛三重态——强准连续太赫兹场中拉比振荡的频率模拟，以及电荷载流子产生高次谐波，电荷载流子在电离后在振荡场中加速并与掺杂离子重新碰撞。这些主题受到气体原子物理模拟现象的强烈推动，特别是通过重碰撞现象对高次谐波的观察代表了阿秒物理热门研究领域的基础。将孤立的原子嵌入主晶体中会导致非线性光学效应（相干时间相当长）在比自由原子低得多的场强和光子能量下发生。由于缺乏合适的辐射源和测量技术，过去很难研究这种现象。基于我们之前的研究，我们打算利用 UCSB-FEL 的独特特性来观察上述效应。这些特性包括 FEL 长太赫兹脉冲的带宽非常小，有利于寻址各个量子态和观察新生成的边带，以及可实现的低辐射频率（低至几百 GHz），支持生成载流子离子碰撞时的高阶谐波。