超短超快激光脉冲的出现为人们探索原子分子中超快电子动力学过程提供了强有力的工具.阿秒脉冲和强激光脉冲电场整形技术能够获得电子波包在亚飞秒时间尺度的动力学信息,发展出了一系列阿秒超快光谱学技术,如阿秒条纹相机、阿秒瞬态吸收谱等,成功地应用于原子、分子和固体中电子运动的探测.其中双色激光场就是通过电场整形技术实现电子相干运动控制和探测的一种重要手段,本文综述了中科院上海光机所强场激光物理国家重点实验室近几年来在双色场控制与测量原子分子超快过程方面的研究工作.
The advent of the ultrafast laser pulse provides the powerful and efficient tool for probing the ultrafast electron dynamics in atoms and molecules.The various nonlinear process induced by the laser-matter interaction allows one to obtain the electron motion information on the sub-femtosecond time scale.A series of the ultrafast spectroscopic technique,such as attosecond streak camera,attosecond transient absorption spectrum,and etc.,have been successfully applied to the probe of electron dynamics in atoms,molecules,and solids.Using two-color field is one of the significant methods to achieve the coherent control and exploring of the electron motion.This paper summarizes recent research activities in the field of the atomic and molecular ultrafast process investigated in State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,including the detection of the electron dynamics of the multi-bound states,measurement of the carrier envelope phase(CEP) and the phase of the attosecond pulse,and the ultrafast electron control with the THz/UV and MIR/IR field.To measure the dynamics of the multi-bound states,a broadband attosecond pulse can be used to ionize the electrons after it is excited by the pump laser.By changing the delay between the pump laser and the attosecond pulse,the measured electrons ionized by the broadband xuv attosecond pulse can present the multi-bound states dynamics simultaneously.The XUV/IR scheme is popularly used in attosecond dynamics measurement.But usually,the IR field is not very strong.We find that,if the IR field is strong enough to induce the above threshold ionization(ATI),the interference between the ATI electron and the electron from XUV pulse can be used to measure the CEP of the attosecond XUV pulse.Besides,if the electron ionized by attosecond pulse can be pushed back to the nuclei,the emission from the recombination can be used to determine the spectral phase of the attosecond pulse,which is an all-optical m