We study the above-threshold ionization(ATI)process of atoms exposed to fundamental and high-frequency lasers with arbitrary ellipticity by applying the frequency-domain theory.It is found that the angular-resolved AT...We study the above-threshold ionization(ATI)process of atoms exposed to fundamental and high-frequency lasers with arbitrary ellipticity by applying the frequency-domain theory.It is found that the angular-resolved ATI spectrum is sensitive to ellipticities of two lasers and emitted angles of the photoelectron.Particularly for the photon energy of the highfrequency laser more than atomic ionization potential,the width of plateau tends to a constant with increasing ellipticity of fundamental field,the dip structure disappears with increasing ellipticity of the high-frequency field.With the help of the quantum channel analysis,it is shown that the angular distribution depends mainly on the ellipticity of high-frequency field in the case that its frequency is high.Moreover,one can see that the maximal and minimal energies in quantum numerical results are in good agreement with the classical prediction.Our investigation may provide theoretical support for experimental research on polarization control of ionization in elliptically polarized two-color laser fields.展开更多
Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor st...Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor structure makes three steps become interatomic coherent process which leads to complicated carrier dynamics and two sources of high harmonic emission: interband polarization and intraband current.The difference of features of high harmonic generation between semiconductors and atoms is strongly linked to the unique presence of intraband motion which manifests itself a nontrivial role in intertwined two dynamics.Here, we review recent experimental and theoretical advances of understanding coupled interband and intraband mechanisms of HHG in semiconductors.Particularly we focus on the influence of intraband motion on the interband excitation, and on the subsequent HHG emission and attosecond pulse generation.展开更多
The semiclassical method based on Feynman’s path-integral is in favor of uncovering the quantum tunneling effect,the classical trajectory description of the electron, and the quantum phase information, which can pres...The semiclassical method based on Feynman’s path-integral is in favor of uncovering the quantum tunneling effect,the classical trajectory description of the electron, and the quantum phase information, which can present an intuitive and transparent physical image of electron’s propagation in comparison with the ab initio time-dependent Schr ¨odinger equation.In this review, we introduce the basic theoretical concepts and development of several semiclassical methods as well as some of their applications in strong-field physics. Special emphasis is placed on extracting time delay on attosecond scale by the combination of the semiclassical method with phase of phase method. Hundreds of millions of trajectories are generally adopted to obtain a relatively high-resolution photoelectron spectrum, which would take a large amount of time. Here we also introduce several optimization approaches of the semiclassical method to overcome the time-consuming problem of violence calculation.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12104285,12074240,12204135,12374260,12264013,12204136,92250303,and 12074418)the Guangdong Basicand Applied Basic Research Foundation (Grant No.2022A1515011742)+5 种基金the Special Scientific Research Program supported by the Shaanxi Education Department (Grant No.22JK0423)the Natural Science Basic Research Program of Shaanxi Province of China (Grant Nos.2023-JC-QN-0085 and 2023-JC-QN-0267)the Hainan Provincial Natural Science Foundation of China (Grant Nos.122CXTD504,123MS002,123QN179,123QN180,and 122QN217)the Sino-German Mobility Programme (Grant No.M-0031)the Xi’an Aeronautical Institute 2023 Innovation and Entrepreneurship Training Program for college students (Grant No.S202311736036)the Course Ideological and Political Education Program (Grant No.23ZLGC5030)。
文摘We study the above-threshold ionization(ATI)process of atoms exposed to fundamental and high-frequency lasers with arbitrary ellipticity by applying the frequency-domain theory.It is found that the angular-resolved ATI spectrum is sensitive to ellipticities of two lasers and emitted angles of the photoelectron.Particularly for the photon energy of the highfrequency laser more than atomic ionization potential,the width of plateau tends to a constant with increasing ellipticity of fundamental field,the dip structure disappears with increasing ellipticity of the high-frequency field.With the help of the quantum channel analysis,it is shown that the angular distribution depends mainly on the ellipticity of high-frequency field in the case that its frequency is high.Moreover,one can see that the maximal and minimal energies in quantum numerical results are in good agreement with the classical prediction.Our investigation may provide theoretical support for experimental research on polarization control of ionization in elliptically polarized two-color laser fields.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674209 and 11774215)the High Level University Projects of Guangdong Province of China(Mathematics,Shantou University)+1 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM),Chinasupport of the Department of Education of Guangdong Province,China(Grant No.2018KCXTD011)
文摘Tunnelling, acceleration, and collision of electrons are the basic events in the process of high harmonic generation(HHG) in strong-field interaction with atoms.However, the periodic array of atoms in semiconductor structure makes three steps become interatomic coherent process which leads to complicated carrier dynamics and two sources of high harmonic emission: interband polarization and intraband current.The difference of features of high harmonic generation between semiconductors and atoms is strongly linked to the unique presence of intraband motion which manifests itself a nontrivial role in intertwined two dynamics.Here, we review recent experimental and theoretical advances of understanding coupled interband and intraband mechanisms of HHG in semiconductors.Particularly we focus on the influence of intraband motion on the interband excitation, and on the subsequent HHG emission and attosecond pulse generation.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.91950101,12074240,and 12104285)Sino-German Mobility Programme(Grant No.M0031)+1 种基金the High Level University Projects of the Guangdong Province,China(Mathematics,Shantou University)the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)。
文摘The semiclassical method based on Feynman’s path-integral is in favor of uncovering the quantum tunneling effect,the classical trajectory description of the electron, and the quantum phase information, which can present an intuitive and transparent physical image of electron’s propagation in comparison with the ab initio time-dependent Schr ¨odinger equation.In this review, we introduce the basic theoretical concepts and development of several semiclassical methods as well as some of their applications in strong-field physics. Special emphasis is placed on extracting time delay on attosecond scale by the combination of the semiclassical method with phase of phase method. Hundreds of millions of trajectories are generally adopted to obtain a relatively high-resolution photoelectron spectrum, which would take a large amount of time. Here we also introduce several optimization approaches of the semiclassical method to overcome the time-consuming problem of violence calculation.