双色阿秒钟的原理和应用  

Principle and application of two-color attoclock

作　　者：韩猛 刘运全[1,2,3] Meng Han;Yunquan Liu(School of Physics and State Key Laboratory for Mesoscopic Physics,Peking University,Beijing 100871,China;Collaborative Innovation Center of Quantum Matter,Beijing 100871,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China)

机构地区：[1]北京大学物理学院,人工微结构与介观物理国家重点实验室,北京100871 [2]量子物质协同创新中心,北京100871 [3]山西大学极端光学协同创新中心,太原030006

出　　处：《科学通报》2021年第8期902-912,共11页Chinese Science Bulletin

基　　金：国家自然科学基金(11434002,11774013)资助。

摘　　要：阿秒钟基于单色圆偏振光场中的角度-时间对应原理,是强场物理中具有阿秒时间分辨本领的重要工具.近年来,双色飞秒光场由于具有灵活的可操作性和丰富的多样性,逐渐发展为调控电子超快动力学的重要手段之一.将阿秒钟和双色光场相结合的双色阿秒钟得到了越来越广泛的关注,成为强场物理研究的前沿方向之一.本文将介绍两种双色阿秒钟方案.首先,基于同向旋转的双色圆偏振光场,提出并演示了一种全新的时间分辨的光电子干涉术,即双指针阿秒钟.利用该方案,提取了电离电子波包的相位信息和振幅信息,揭示了电子在势垒下的隧穿动力学.其次,提出并演示了一种改进型阿秒钟,在一束圆偏振飞秒激光场中加入另一束线偏振的倍频光来校准阿秒钟,使得测量隧穿时间所对应的光电子偏移角更加准确可靠.另外,我们在理论上证明了瞬时隧穿和Wigner延时隧穿这两种看似对立的隧穿图像可以被统一在同一个理论框架下(即强场近似理论)进行描述.对于改进型阿秒钟,这两种隧穿图像的理论结果都与实验结果相符合.Time-resolving ultrafast electron dynamics driven by lights in atoms and molecules is one of the central topics in both science and technology,as a prerequisite for controlling the electron dynamics and creating unprecedented functions to serve for human.Photoionization by intense lasers is the fundamental interaction between lights and atoms.For strongfield ionization,the amplitude and the phase of the ionized electron wave packet could give direct insights of electron dynamics in the classically forbidden,sub-Coulomb-barrier region.Electron tunneling through the suppressed Coulomb potential and traveling in continuum leave fingerprints not only on the amplitude of the electron wave packet,but also on its phase distribution.Recently,benefiting from that the laser pulse duration approaches to the natural time scale of intraatomic electron dynamics,one was allowed to image the amplitude and the phase of an electron wave function on the attosecond scale using new metrologies combined with attosecond light pulses,such as attosecond streaking camera and the technique of reconstruction of attosecond beating by interference of two-photon transition.Alternatively,attoclock is based on the angle-time mapping principle in one-color circularly polarized femtosecond light fields,without resorting to the attosecond light pulses.It is originally introduced as a powerful method to address the issue of tunneling time delays with the attosecond time resolution in strong-field physics.In recent years,due to the flexible manipuility and the rich diversity of the two-color femtosecond light fields,the two-color fields have gradually become an important method to control the ultrafast electron dynamics driven by intense lasers.The two-color attoclock combined with attoclock and twocolor fields,then attracts the increasing attention,and hence becomes the research front of strong-field physics.In this review,we will introduce two kinds of the two-color attoclock.First,based on the co-rotating two-color light fields,we demonstrate a no

关 键 词：强场电离 阿秒钟 双色光场 隧穿时间 

分 类 号：TN24[电子电信—物理电子学]