We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position...We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse.This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics.Notably,we observe a modulated shift in the created harmonic photon energy,spanning an impressive range of 1.2 eV.This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse,directly influencing the position of the peak frequency emission.Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse,offering valuable insights into the underlying mechanisms driving this phenomenon.Furthermore,our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered.We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores.This observation introduces an innovative approach for generating semi-integer order harmonics,thus expanding our understanding of high-order harmonic generation.Ultimately,our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications,particularly those involving precise spectral control and the generation of unique harmonic patterns.展开更多
High-order harmonic generation of the cyclo[18]carbon(C_(18) ) molecule under few-cycle circularly polarized laser pulse is studied by time-dependent density functional theory. Compared with the harmonic emission of t...High-order harmonic generation of the cyclo[18]carbon(C_(18) ) molecule under few-cycle circularly polarized laser pulse is studied by time-dependent density functional theory. Compared with the harmonic emission of the ring molecule C_(6)H_(6) having similar ionization potential, the C_(18) molecule has higher efficiency and cutoff energy than C_(6)H_(6) with the same laser field parameters. Further researches indicate that the harmonic efficiency and cutoff energy of the C_(18) molecule increase gradually with the increase of the laser intensity of the driving laser or decrease of the wavelength, both are larger than those of the C_(6)H_(6) molecule. Through the analysis of the time-dependent evolution of the electronic wave packets, it is also found that the higher efficiency of harmonic generation can be attributed to the larger spatial scale of the C_(18) molecule,which leads to a greater chance for the ionized electrons from one atom to recombine with others of the parent molecule.Selecting the suitable driving laser pulse, it is demonstrated that high-order harmonic generation in the C_(18) molecule has a wide range of applications in producing circularly polarized isolated attosecond pulse.展开更多
According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are...According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization;while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels.展开更多
We simulate the dynamic response of H^(+)_(2) in a linearly polarized laser field by numerically solving the time-dependent Schr?dinger equation.The elliptically polarized high-order harmonics generated by H^(+)_(2)ir...We simulate the dynamic response of H^(+)_(2) in a linearly polarized laser field by numerically solving the time-dependent Schr?dinger equation.The elliptically polarized high-order harmonics generated by H^(+)_(2)irradiated by the linearly polarized laser field are systematically investigated.The result shows that the amplitude and rotation of the ellipticity of harmonics are affected by the alignment angle and internuclear distance of the molecule.Analyzing the change in forces acted on the ionized electrons and the trajectories of the electrons,the phenomena are found to be due to the change in the direction of the total Coulomb forces from the two nuclei felt by the recollided ionized electrons in the direction perpendicular to the laser polarization direction.Based on the influence law,we can select the harmonics with a specific frequency band under different alignment angles and then synthesize the isolated attosecond pulses with different rotations,which can be continuously converted from right-handed circular polarization,linear polarization,and left-handed circular polarization by changing the alignment angle.This study provides a new possible approach to the real-time detection of molecular states by using attosecond pulses and obtaining more optimized harmonics with molecular properties.展开更多
The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and doubl...The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and double ionization process are calculated by the BM theory and their results are in good agreement with those calculated by numerically solving the time-dependent Schrodinger equation. The analyses of the types, trajectories, and forces of Bohmian particles(BPs)undergoing the single and double ionizations indicate that the re-collision process accounts for a considerable proportion in the singly ionized cases. Furthermore, the analysis of the work done by the external force acting on the BPs shows that the quantum force plays an important role in the re-collision process. This work is helpful in understanding the ionization of two-electron atom in an intense laser field.展开更多
Resonance enhanced two-photon ionization process of hydrogen atom via the resonant laser pulse is studied by Bohmian mechanics (BM) method. By analyzing the trajectories and energies of Bohmian particles (BPs), we fin...Resonance enhanced two-photon ionization process of hydrogen atom via the resonant laser pulse is studied by Bohmian mechanics (BM) method. By analyzing the trajectories and energies of Bohmian particles (BPs), we find that under the action of high frequency and low intensity multi-circle resonant laser pulses, the ionized BPs first absorb one photon completing the excitation, and then absorb another photon, completing the ionization after staying in the first excited state for a period of time. The analysis of work done by the forces shows that the electric field force and quantum force play a major role in the whole ionization process. At the excitation moment and in the excitation-ionization process, the effect of the quantum force is greater than that of the electric field force. Finally, we discuss the principle of work and energy for BPs, and find that the electric field force and quantum force are non-conservative forces whose work is equal to the increment of mechanical energy of the system. In addition, it is proved that the quantum potential energy actually comes from the kinetic energy of the system and the increment of kinetic energy is equal to that of the kinetic energy of the system.展开更多
Universality of the dynamic characteristic relationship between the characteristic time tc and the two-electron Coulomb interaction energy V12 of the ground state in the two-photon double ionization process is investi...Universality of the dynamic characteristic relationship between the characteristic time tc and the two-electron Coulomb interaction energy V12 of the ground state in the two-photon double ionization process is investigated via changing the parameters of the two-electron atomic system and the corresponding laser conditions.The numerical results show that the product tcV12 keeps constant around 4.1 in the cases of changing the nucleus charge,the electron charge,the electron mass,and changing simultaneously the nucleus charge and the electron charge.These results demonstrate that the dynamic characteristic relationship in the two-photon double ionization process is universal.This work sheds more light on the dynamic characteristic relationship in ultrafast processes and may find its application in measurements of attosecond pulses.展开更多
We simultaneously investigate variations of a low order harmonic and photoelectron emission with an incident laser intensity by solving the time-dependent Schr6dinger equation in a momentum space. It can be found that...We simultaneously investigate variations of a low order harmonic and photoelectron emission with an incident laser intensity by solving the time-dependent Schr6dinger equation in a momentum space. It can be found that, the intensity of low order harmonic and photoelectron are gradually enhanced with the increase of the laser intensity, when the laser frequency is not in resonance with the transition frequency between the laser-induced high excited states and the ground state. If the resonance occurs, the intensity of the lower order harmonic is reduced and the interference can be observed in the lower order photoelectron spectra.展开更多
We investigated the ionization of an atom with different orbital angular momenta in a high-frequency laser field by solving the time-dependent Schr¨odinger equation.The results showed that the ionization stabiliz...We investigated the ionization of an atom with different orbital angular momenta in a high-frequency laser field by solving the time-dependent Schr¨odinger equation.The results showed that the ionization stabilization features changed with the relative direction between the angular momentum of the initial state and the vector field of the laser pulse.The ionization mechanism of the atom irradiated by a high frequency was explained by calculating the transition matrix and evolution of the time-dependent wave packet.This study can provide comprehensive understanding to improve atomic nonadiabatic ionization.展开更多
The wave packet evolution of an atom irradiated by an intense laser pulse is systematically investigated by using the numerical solution of the time-dependent Schr?dinger equation.There are two types of spatial interf...The wave packet evolution of an atom irradiated by an intense laser pulse is systematically investigated by using the numerical solution of the time-dependent Schr?dinger equation.There are two types of spatial interference structures in the time-dependent evolution of the atomic wave packet.With the increasing of the evolution time,the interference fringe spacing for typeⅠ(typeⅡ)becomes larger(smaller).As the wavelength of the incident laser increases,the interference of the wave packet is changed from typeⅡto typeⅠ,and the shift of interference type can be attributed to the contribution of excited states by using the energy analysis of the time-dependent wave function.展开更多
We theoretically investigate the photoelectron emission from an atom irradiated by an amplitude modulated sinusoidally phase-modulated pulse through solving the time-dependent Schr¨odinger equation in the momentu...We theoretically investigate the photoelectron emission from an atom irradiated by an amplitude modulated sinusoidally phase-modulated pulse through solving the time-dependent Schr¨odinger equation in the momentum space. By controlling the phase amplitude of the pulse in the frequency domain, it can be found that the photoelectron spectra appear as explicit interference phenomena, which originated from the interference between the directly ionized electron and the ionization of the pre-excited atom from different subpulses.展开更多
Double ionization of H2 in a co-rotating two-color circularly polarized(TCCP)laser field is theoretically investigated.By changing the ratio of electric field peak amplitudes of the TCCP laser pulses,the double ioniza...Double ionization of H2 in a co-rotating two-color circularly polarized(TCCP)laser field is theoretically investigated.By changing the ratio of electric field peak amplitudes of the TCCP laser pulses,the double ionization probability as a function of the laser intensity shows a clear knee structure,which is suppressed significantly in the case of the atom.Due to the large spatial range of the electronic initial distribution,with the analysis of classical trajectories of ionized electrons,it is found that the ionization of the electron in the farther distance increases the probability of recollision.Furthermore,the yield of nonsequential double ionization created by the recollision can be enhanced by controlling the amplitude ratio of the TCCP laser field.展开更多
Continuum wavepacket interference is investigated by numerically solving the time-dependent SchrSdinger equation for the interaction of hydrogen atoms with laser fields. The obtained wavepacket evolution indicates tha...Continuum wavepacket interference is investigated by numerically solving the time-dependent SchrSdinger equation for the interaction of hydrogen atoms with laser fields. The obtained wavepacket evolution indicates that, in the over-the-barrier ionization regime (1016 W/cm2), the continuum-continuum (CC) interference of ionizing electrons becomes the main process in high- order harmonics generation (HHG), compared with continuum-bound (CB) transition, as reported by Kohler et al. [Phys. Rev. Lett. 105(20), 203902 (2010)]. We propose a two-color laser field scheme for controlling the quantum trajectories of ionizing electrons and for extending the CC harmonic energy. As a result, a high energy platform occurs in the HHG spectrum, which entirely originates from the CC harmonics, with a cutoff adjustable by the relative phase of the two-color fields. This provides further understanding of the dynamic feature of atoms and molecules in super intense laser fields and provides an opportunity to image the atomic or molecular potential.展开更多
基金This project was supported by the National Key Research and Development Program of China(Grant Nos.2022YFE134200 and 2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.11604119,12104177,11904192,12074145,and 11704147)the Fundamental Research Funds for the Central Universities(Grant Nos.GK202207012 and QCYRCXM-2022-241).
文摘We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse.This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics.Notably,we observe a modulated shift in the created harmonic photon energy,spanning an impressive range of 1.2 eV.This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse,directly influencing the position of the peak frequency emission.Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse,offering valuable insights into the underlying mechanisms driving this phenomenon.Furthermore,our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered.We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores.This observation introduces an innovative approach for generating semi-integer order harmonics,thus expanding our understanding of high-order harmonic generation.Ultimately,our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications,particularly those involving precise spectral control and the generation of unique harmonic patterns.
基金Project supported by the National Key Research and Development Program of China (Grant No.2019YFA0307700)the National Natural Science Foundation of China (Grant Nos.12204214,12074145,and 11627807)。
文摘High-order harmonic generation of the cyclo[18]carbon(C_(18) ) molecule under few-cycle circularly polarized laser pulse is studied by time-dependent density functional theory. Compared with the harmonic emission of the ring molecule C_(6)H_(6) having similar ionization potential, the C_(18) molecule has higher efficiency and cutoff energy than C_(6)H_(6) with the same laser field parameters. Further researches indicate that the harmonic efficiency and cutoff energy of the C_(18) molecule increase gradually with the increase of the laser intensity of the driving laser or decrease of the wavelength, both are larger than those of the C_(6)H_(6) molecule. Through the analysis of the time-dependent evolution of the electronic wave packets, it is also found that the higher efficiency of harmonic generation can be attributed to the larger spatial scale of the C_(18) molecule,which leads to a greater chance for the ionized electrons from one atom to recombine with others of the parent molecule.Selecting the suitable driving laser pulse, it is demonstrated that high-order harmonic generation in the C_(18) molecule has a wide range of applications in producing circularly polarized isolated attosecond pulse.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474348,11674198,11425414,and 11774411)
文摘According to the frequency-domain theory, we investigate the asymmetric structure of above-threshold ionization(ATI) spectrum of an atom in two-color elliptically polarized(EP) laser fields. When both laser fields are linearly polarized(LP), the spectrum shows that the multi-plateau structure is symmetric about the emitted angle of electron at π/2, while the spectrum becomes asymmetric and shifts rightwards with the increase of the EP degree of the IR laser field. Since the total ATI process is regarded as including direct ATI and the rescattering ATI, we analyze the spectrum structure of direct ATI and rescattering ATI separately. Using the saddle-point approximation, we find that for direct ATI, the fringes on the spectrum are mainly attributed to the fact that the ionization probability becomes very small when the direction of emitted electrons is perpendicular to the direction of the XUV laser polarization;while for the rescattering ATI, the interference fringes on the spectrum mainly come from the superposition of the waist structures on the spectra of all sub-channels.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700)the Science Foundation of China(Grant Nos.11627807,11774129,and 12074145)+1 种基金the High Performance Computing Center of Jilin University for supercomputer timethe high performance computing cluster Tiger@IAMP。
文摘We simulate the dynamic response of H^(+)_(2) in a linearly polarized laser field by numerically solving the time-dependent Schr?dinger equation.The elliptically polarized high-order harmonics generated by H^(+)_(2)irradiated by the linearly polarized laser field are systematically investigated.The result shows that the amplitude and rotation of the ellipticity of harmonics are affected by the alignment angle and internuclear distance of the molecule.Analyzing the change in forces acted on the ionized electrons and the trajectories of the electrons,the phenomena are found to be due to the change in the direction of the total Coulomb forces from the two nuclei felt by the recollided ionized electrons in the direction perpendicular to the laser polarization direction.Based on the influence law,we can select the harmonics with a specific frequency band under different alignment angles and then synthesize the isolated attosecond pulses with different rotations,which can be continuously converted from right-handed circular polarization,linear polarization,and left-handed circular polarization by changing the alignment angle.This study provides a new possible approach to the real-time detection of molecular states by using attosecond pulses and obtaining more optimized harmonics with molecular properties.
基金Project supported by the Jilin Provincial Science and Technology Development Plan Program for Excellent Youth Talents,China(Grant No.20180520174JH)the National Natural Science Foundation of China(Grant Nos.11704145,11904050,11774129,11747007,11534004,and 12074145).
文摘The ionization dynamics of two-electron atom in an intense laser field is studied by the Bohmian mechanics(BM)theory, and the xenon atomic potential function is used as a model. The single ionization process and double ionization process are calculated by the BM theory and their results are in good agreement with those calculated by numerically solving the time-dependent Schrodinger equation. The analyses of the types, trajectories, and forces of Bohmian particles(BPs)undergoing the single and double ionizations indicate that the re-collision process accounts for a considerable proportion in the singly ionized cases. Furthermore, the analysis of the work done by the external force acting on the BPs shows that the quantum force plays an important role in the re-collision process. This work is helpful in understanding the ionization of two-electron atom in an intense laser field.
基金Project supported by Jilin Province Science and Technology Development Plan Project-Excellent Youth Talents Fund Project,China(Grant No.20180520174JH)the National Natural Science Foundation of China(Grant Nos.1170414511904050,11774129,11747007,and 11534004).
文摘Resonance enhanced two-photon ionization process of hydrogen atom via the resonant laser pulse is studied by Bohmian mechanics (BM) method. By analyzing the trajectories and energies of Bohmian particles (BPs), we find that under the action of high frequency and low intensity multi-circle resonant laser pulses, the ionized BPs first absorb one photon completing the excitation, and then absorb another photon, completing the ionization after staying in the first excited state for a period of time. The analysis of work done by the forces shows that the electric field force and quantum force play a major role in the whole ionization process. At the excitation moment and in the excitation-ionization process, the effect of the quantum force is greater than that of the electric field force. Finally, we discuss the principle of work and energy for BPs, and find that the electric field force and quantum force are non-conservative forces whose work is equal to the increment of mechanical energy of the system. In addition, it is proved that the quantum potential energy actually comes from the kinetic energy of the system and the increment of kinetic energy is equal to that of the kinetic energy of the system.
基金Supported by the National Natural Science Foundation of China(Grant Nos.91850209,11774129,and 11774411)the National Key Research and Development Program of China(Grant Nos.2019YFA0307700 and 2016YFA0401100)。
文摘Universality of the dynamic characteristic relationship between the characteristic time tc and the two-electron Coulomb interaction energy V12 of the ground state in the two-photon double ionization process is investigated via changing the parameters of the two-electron atomic system and the corresponding laser conditions.The numerical results show that the product tcV12 keeps constant around 4.1 in the cases of changing the nucleus charge,the electron charge,the electron mass,and changing simultaneously the nucleus charge and the electron charge.These results demonstrate that the dynamic characteristic relationship in the two-photon double ionization process is universal.This work sheds more light on the dynamic characteristic relationship in ultrafast processes and may find its application in measurements of attosecond pulses.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0403300)the National Natural Science Foundation of China(Grant Nos.11774129,11274141,11627807,11604119,and 11534004)the Jilin Provincial Research Foundation for Basic Research,China(Grant No.20170101153JC)
文摘We simultaneously investigate variations of a low order harmonic and photoelectron emission with an incident laser intensity by solving the time-dependent Schr6dinger equation in a momentum space. It can be found that, the intensity of low order harmonic and photoelectron are gradually enhanced with the increase of the laser intensity, when the laser frequency is not in resonance with the transition frequency between the laser-induced high excited states and the ground state. If the resonance occurs, the intensity of the lower order harmonic is reduced and the interference can be observed in the lower order photoelectron spectra.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700)the National Natural Science Foundation of China(Grant Nos.12074145,11627807,11774175,11534004,11774129,11604119,and 11975012)Fundamental Research Funds for the Central Universities of China(Grant No.30916011207)。
文摘We investigated the ionization of an atom with different orbital angular momenta in a high-frequency laser field by solving the time-dependent Schr¨odinger equation.The results showed that the ionization stabilization features changed with the relative direction between the angular momentum of the initial state and the vector field of the laser pulse.The ionization mechanism of the atom irradiated by a high frequency was explained by calculating the transition matrix and evolution of the time-dependent wave packet.This study can provide comprehensive understanding to improve atomic nonadiabatic ionization.
基金Project partially supported by the National Key Research and Development Program of China(Grant Nos.2019YFA0307700 and 2017YFA0403300)the National Natural Science Foundation of China(Grant Nos.11627807,11534004,11975012,and 11774129)+1 种基金the Jilin Provincial Research Foundation for Basic Research,China(Grant No.20170101153JC)the Science and Technology Project of the Jilin Provincial Education Department,China(Grant No.JJKH20190183KJ)
文摘The wave packet evolution of an atom irradiated by an intense laser pulse is systematically investigated by using the numerical solution of the time-dependent Schr?dinger equation.There are two types of spatial interference structures in the time-dependent evolution of the atomic wave packet.With the increasing of the evolution time,the interference fringe spacing for typeⅠ(typeⅡ)becomes larger(smaller).As the wavelength of the incident laser increases,the interference of the wave packet is changed from typeⅡto typeⅠ,and the shift of interference type can be attributed to the contribution of excited states by using the energy analysis of the time-dependent wave function.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0403300)the National Natural Science Foundation of China(Grants Nos.11774129,11274141,11627807,11604119,and 11534004)the Jilin Provincial Research Foundation for Basic Research,China(Grant No.20170101153JC)
文摘We theoretically investigate the photoelectron emission from an atom irradiated by an amplitude modulated sinusoidally phase-modulated pulse through solving the time-dependent Schr¨odinger equation in the momentum space. By controlling the phase amplitude of the pulse in the frequency domain, it can be found that the photoelectron spectra appear as explicit interference phenomena, which originated from the interference between the directly ionized electron and the ionization of the pre-excited atom from different subpulses.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700 and No.2017YFA0403300)National Natural Science Foundation of China(NSFC)(Grants No.11627807,No.11774175,No.11534004,No.11774129 and No.11975012)+2 种基金the Jilin Provincial Research Foundation for Basic Research,China(Grant No.20170101153JC)the Science and Technology project of the Jilin Provincial Education Department(Grant No.JJKH20190183KJ)the outstanding Youth project of Taizhou University(Grant No.2019JQ002)。
文摘Double ionization of H2 in a co-rotating two-color circularly polarized(TCCP)laser field is theoretically investigated.By changing the ratio of electric field peak amplitudes of the TCCP laser pulses,the double ionization probability as a function of the laser intensity shows a clear knee structure,which is suppressed significantly in the case of the atom.Due to the large spatial range of the electronic initial distribution,with the analysis of classical trajectories of ionized electrons,it is found that the ionization of the electron in the farther distance increases the probability of recollision.Furthermore,the yield of nonsequential double ionization created by the recollision can be enhanced by controlling the amplitude ratio of the TCCP laser field.
基金Acknowledgements This work was supported by the National Basic Research Program of China (973 Program) (Grant No. 2013CB922200) and the National Natural Science Foundation of China (Grants Nos. 1127403, 11274141, and 11534004). We also acknowledge the High Performance Computing Center (HPCC) of Jilin University for supercomputer time.
文摘Continuum wavepacket interference is investigated by numerically solving the time-dependent SchrSdinger equation for the interaction of hydrogen atoms with laser fields. The obtained wavepacket evolution indicates that, in the over-the-barrier ionization regime (1016 W/cm2), the continuum-continuum (CC) interference of ionizing electrons becomes the main process in high- order harmonics generation (HHG), compared with continuum-bound (CB) transition, as reported by Kohler et al. [Phys. Rev. Lett. 105(20), 203902 (2010)]. We propose a two-color laser field scheme for controlling the quantum trajectories of ionizing electrons and for extending the CC harmonic energy. As a result, a high energy platform occurs in the HHG spectrum, which entirely originates from the CC harmonics, with a cutoff adjustable by the relative phase of the two-color fields. This provides further understanding of the dynamic feature of atoms and molecules in super intense laser fields and provides an opportunity to image the atomic or molecular potential.