作者单位
摘要
长春理工大学物理学院,吉林 长春 130022
利用强场近似理论开展了正交偏振双色场与氦原子相互作用产生高次谐波和阿秒脉冲的理论研究。正交偏振双色场由少周期的4 fs钛宝石驱动脉冲激光和与它偏振方向垂直的8 fs倍频控制脉冲构成。研究发现,通过合理选择两束脉冲之间的相对相位,能够控制高次谐波发射过程中长、短电子轨道的选择。当相对相位调整为1.2π时,平台谐波主要来自短轨道电子的贡献,由于其运动时间短、波包扩散少,且没有与长轨道电子谐波产生干涉,沿驱动脉冲电场方向的高次谐波谱具有较高强度和较小调制幅度的超连续平台区,通过对第120次到第180次超连续谐波进行傅里叶变换,可产生脉宽为54 as的高强度孤立阿秒脉冲。所提方案对组合脉冲相对相位的选取要求并不严苛,在0.3π的变化范围内皆可获得脉宽较短的孤立阿秒脉冲,同时控制脉冲电场强度的变化对上述数值模拟结果的影响也很小。
超快光学 高次谐波产生 阿秒脉冲 正交偏振双色场 电子轨道 ultrafast optics high-order harmonic generation attosecond pulse orthogonally polarized two-color field electron trajectory 
光学学报
2023, 43(13): 1332001
Author Affiliations
Abstract
1 School of Science, Hainan University, Haikou 570228, China
2 Research Center for Advanced Optics and Photoelectronics, Department of Physics, College of Science, Shantou University, Shantou 515063, China
3 Institute of Mathematics, Shantou University, Shantou 515063, China
4 Physics Program, Guangdong Technion - Israel Institute of Technology, Shantou 515063, China
5 Technion - Israel Institute of Technology, Haifa 32000, Israel
High-harmonic generation in metasurfaces, driven by strong laser fields, has been widely studied. Compared to plasma, all-dielectric nanoscale metasurfaces possess larger nonlinearity response and higher damage threshold. Additionally, it can strongly localize the driven field, greatly enhancing its peak amplitude. In this work, we adopt a Fano resonant micro-nano structure with transmission peaks at different wavelengths and explore its nonlinear response by both single and two-color pump fields. Compared to the high-order harmonics induced by the first resonant wavelength, the intensity of the high-harmonic radiation results is enhanced by one order of magnitude, when the metasurface is driven by various resonant and non-resonant wavelength combinations of a two-color field.
metamaterial nanostructure Fano resonance high-harmonic generation two-color field 
Chinese Optics Letters
2021, 19(12): 123202
Yi Jia 1Li Guo 2,*Shilin Hu 3Xinyan Jia 1,**[ ... ]Jing Chen 5,6,***
Author Affiliations
Abstract
1 School of Physics, Southwest Jiaotong University, Chengdu 610031, China
2 Department of Physics, Shanghai Normal University, Shanghai 200234, China
3 Guangdong Provincial Key Laboratory of Quantum Metrology and Sensing & School of Physics and Astronomy, Sun Yat-sen University (Zhuhai Campus), Zhuhai 519082, China
4 Key Laboratory for Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
5 Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
6 Center for Advanced Material Diagnostic Technology, College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
We calculate the time-energy distribution (TED) and ionization time distribution (ITD) of photoelectrons emitted by a double-extreme-ultraviolet (XUV) pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation. For a double-XUV pulse, besides two identical broad distributions generated by two XUV pulses, many interference fringes resulting from the interference between electrons generated, respectively, by two pulses appear in the TED. After adding an IR field, the TED intuitively exhibits the effect of the IR field on the electron dynamics. The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields, the origin of which is attributed to the change of the electric field induced by the IR field. Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.
Wigner distribution two-color field time-energy distribution attosecond physics strong field approximation 
Chinese Optics Letters
2021, 19(12): 123201
作者单位
摘要
1 长江大学物理科学与技术学院,湖北 荆州 434023
2 武汉光电国家实验室,湖北 武汉 430074
采用由2000 nm中红外驱动场和1000 nm弱倍频调制场组成的双色场作为驱动源,提出了产生水窗波段宽带高次谐波谱的新方法。弱倍频场对原子中电子的电离阶段进行调制,不仅扩大了 连续谱的带宽,而且大大提高了连续谱的产生效率。通过求解一维氦原子模型下含时薛定谔方程,发现该双色场驱动下能够得到谱宽为190 eV的连续谱,并且较2000 nm中红外单色驱动下,连续谱 谐波的效率提高了两个数量级。此外,计算中还发现调整双色场的相对载波包络相位,能够增强一个轨道电子的贡献同时抑制另一个电子轨道的贡献,利用这种方法能够得到脉宽为70 as的单阿秒脉冲。
X射线光学 高次谐波 双色场 连续谱 X-ray optics high-order harmonic generation two-color field continuum spectrum 
量子电子学报
2012, 29(5): 530
作者单位
摘要
中国科学院上海光学精密机械研究所强光光学开放实验室,上海 201800
提高高次谐波效率一直是强场物理研究中的一个重要课题,对此人们采取了很多方法,如采用双色场、实现相位匹配、附加一个强电场或强磁场等.本文在研究双色场高次谐波的过程中,发现原子的能级结构对于高次谐波的产生效率有极大的影响,据此提出利用附加共振高频场来大幅度提高高次谐波的产生效率.
双色场高次谐波 原子能级结构 原子光电离 two color field high order harmonic generation atomic photoionization 
光学学报
2001, 21(10): 1153

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