Non-linear Optical Responses and Many-Body Effects of Excitonic Fano Resonance States

激子法诺共振态的非线性光学响应和多体效应

• 批准号: 16540279
• 负责人: HINO Ken-ichi
• 金额: $ 2.5万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540279/
• 关键词: Semiconductor Superlattices; Wannier-Stark Ladder; Zener Effect; Floquet State; Semiconductor Bloch Equations; Non-Linear Optical Response; Many-Body Effect; Exciton; 動的Zener効果; 2次Zeeman効果; Wannier-Stark ladder; Fano共鳴; Zenerトンネリング; 動的Wannier

The present research project is aimed at the theoretical understanding of the non-linear optical response and the many-body effect on semiconductor superlattices with a static electric field along the direction of the crystal growth, termed the Wannier Stark ladder (WSL). In particular, an attention is paid to such two effects on excitonic Fano resonance (FR) states ascribable to the low dimensionality of the semiconductor concerned. The main research results are enumerated in the following :(1) Zener effects on WSL-FR states under an intense static electric fieldPhotoabsorption spectra of an exciton of this system are simulated based on the multi-channel scattering theory. The strong anticrossing between the subband energies of a carrier (an electron or a hole) and the conspicuous delocalization of the associated wavefunctions are observed under the particular applied electric field giving rise to the Zener resonance. This results in strong modulation of the exciton spectra as a funct … More ion of strength of the electric field. To put it concretely, the red shift of the absorption edge and the irregular variation of the FR profile are found.(2) Asymmetric doublet splitting of the dressed exciton FR state in the degenerate four-wave mixing (DFWM) spectroscopyBased on the semiconductor Bloch equations in view of the many-body effect, the DFWM signals of the WSL are examined, where both strong pump pulse laser and relatively weak probe pulse laser are irradiated on this target. It is known that the symmetric doublet splitting attributed to an ordinary exciton bound state is observed in the spectrally-resolved DFWM spectra, which is termed the Autler-Townes splitting. On the other hand, when the exciton FR state is particularly concerned, it is found that the spectra become asymmetric, resulting from the interference of the microscopic polarization coherence and the FR wave function with the phase reflecting the degree of the magnitude of the Fano-q value. The profile and the energy position of the novel doublet greatly depend on the many-body effect as well as the intensity of the pump light.(3) ac-Zener effect of the dynamic WSL (DWSL)The system of the WSL strongly coupled with a THz laser with periodic repetition is termed the DWSL. It is well known that the Floquet state of the DWSL can be coherently controlled by means of a monochromatic laser. Here, the ac-Zener effect on the DWSL driven by a periodic pulse train is examined by calculating the quasienergies and the absorption spectra of the associated Floquet states. The novel possibility of the quantum control is found that the ac-Zener effect of the DWSL can be coherently removed when the wave form of the pulse is of the either square or saw-toothed shape. On the other hand, as regards the periodic pulse train with other wave forms, it is found that anomalous negative absorption manifest itself with increasing the intensity of the laser concerned. Less

本研究项目旨在从理论上理解沿晶体生长方向具有静电场的半导体超晶格的非线性光学响应和多体效应，特别是称为万尼尔斯塔克梯子（WSL）。重点研究了半导体低维数对激子法诺共振（FR）态的两种影响，主要研究成果如下：（1）WSL-FR态的齐纳效应。基于多通道散射理论模拟了该系统的强静电场激子的光吸收光谱，观察到载流子（电子或空穴）的子带能量之间的强反交叉和相关波函数的显着离域。特定的施加电场引起齐纳共振，这导致激子光谱作为电场强度的函数进行强烈调制。具体来说，就是红移。 (2)简并四波混频(DFWM)光谱中修饰激子FR态的不对称双峰分裂基于多体半导体Bloch方程为了验证WSL效应，我们检查了WSL的DFWM信号，其中强泵浦脉冲激光和相对较弱的探测脉冲激光都照射在该目标上，已知对称双峰分裂归因于普通的。在光谱分辨的 DFWM 光谱中观察到激子束缚态，这被称为奥特勒-汤斯分裂。另一方面，当特别关注激子 FR 态时，发现光谱由于 DFWM 的干扰而变得不对称。微观偏振相干性和FR波函数的相位反映了Fano-q值的大小程度，新型双合峰的轮廓和能量位置很大程度上取决于(3)动态WSL(DWSL)的交流齐纳效应WSL与具有周期性重复的太赫兹激光器强耦合的系统被称为DWSL。众所周知，DWSL 的 Floquet 态可以通过单色激光器进行相干控制。这里，通过计算准能量和相关 Floquet 态的吸收光谱发现，当脉冲波形为方形或锯齿形时，DWSL 的交流齐纳效应可以被相干地消除。另一方面，对于其他波形的周期脉冲串，发现随着相关激光强度的增加，反常负吸收表现得较少。

项目成果

Removal of interminiband interactions in dynamic Wannier-Stark ladder by means of a pulse train with periodic repetition

通过周期性重复的脉冲序列消除动态 Wannier-Stark 阶梯中的小带间相互作用

• 发表时间: 2006
• 期刊: Solid State Communications 138
• 作者: K.Hino;N.Toshima
• 通讯作者: N.Toshima

Interacting dynamic Wannier-Stark ladder driven by a periodic pulse train

由周期性脉冲串驱动的交互动态 Wannier-Stark 梯子

• 发表时间: 2008
• 期刊: Physical Review B 77
• 作者: K. Hino;X. M. Tong and N. Toshima
• 通讯作者: X. M. Tong and N. Toshima

Phase dependent atomic ionization in few-cycle laser fields : direct ionization and rescattering

少周期激光场中的相位相关原子电离：直接电离和再散射

• 发表时间: 2006
• 期刊: Phys. Rev. A 74
• 作者: X.M.Tong;K.Hino;N.Toshima
• 通讯作者: N.Toshima

Dimensionality transitions of exciton Fano-resonance spectra in a semiconductor Wannier-Stark ladder

半导体 Wannier-Stark 梯中激子 Fano 共振光谱的维数跃迁

• 发表时间: 2005
• 期刊: Solid State Communications 135
• 作者: K.Hino;N.Toshima
• 通讯作者: N.Toshima

Spectral modulation of exciton Fano resonance due to Zener breakdown in strongly biased superlattices

强偏置超晶格中齐纳击穿引起的激子法诺共振的光谱调制

• 发表时间: 2005
• 期刊: Phys. Rev. B 71
• 作者: K.Hino;N.Toshima
• 通讯作者: N.Toshima