Theoretical Study On The Characteristics Of High-order Harmonic Generation From One-Dimensional Periodic Potential

With the rapid development of laser technology,many new physical phenomena can be observed during the interaction between strong laser field with atoms and molecules.And the high-order harmonic generation,providing an efficient tool to achieve the attosecond pulse,has been one of the important research topics in the strong laser field.The lower harmonic yields from the atomic and molecular systems limit the development of nonlinear attosecond science.However,compared with the gas system,the solid system owns the special characters such as high density and diverse spatial structure.The harmonics from the solid system make it possible to achieve the high-intensity attosecond pulse,which has been a hot topic.Based on the one-dimensional periodic model potential,the characteristics of high-order harmonic generation are studied by numerically solving the time-dependent Schr?dinger equation.The main research contents include the following two aspects:(1)The effect of the two-color field on the solid harmonic efficiency.Numerical simulations show that the chirped control pulse can effectively improve the intensity of the second plateau in the two-color field,and it can be further enhanced by adjusting the frequency of the chirped control pulse.Moreover,the quantum trajectory in the harmonic generation process can be manipulated by changing the delay time between two-color field.And then the single quantum path tends to contribute to second plateau,which provides the theoretical foundation for the generation of the intense attosecond pulse.(2)The effects of carrier envelope phase on the solid harmonic structure.The numerical results show that the solid harmonics exhibit three different oscillating structures with the moderate increasing of the carrier envelope phases.Moreover,the harmonic cutoff energy in different oscillating structures shows different dependence on the carrier envelope phases.In addition,the electronics dynamics are studied by the electron populations in each energy band at different carrier envelope phases.