We study high-order harmonic generation（HHG） from multi-center asymmetric linear molecules numerically and analytically. Our simulations show that odd and even HHG spectra of the asymmetric multi-center system respo...We study high-order harmonic generation（HHG） from multi-center asymmetric linear molecules numerically and analytically. Our simulations show that odd and even HHG spectra of the asymmetric multi-center system respond differently to the change of the molecular structure. Specifically, when the internuclear distances between these nuclei of the molecule have a small change, the odd spectra usually do not change basically, but the even spectra differ remarkably. Based on this phenomenon, a simple procedure is proposed to probe the positions of these nuclei with odd–even HHG. Our results shed light on attosecond probing of the structure of multi-center molecules using HHG.展开更多
The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we ...The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states for time dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a demonstration of our general approach.展开更多
We study odd–even high-order harmonic generation（HHG） from oriented asymmetric molecules He H2＋numerically and analytically. The variational method is used to improve the analytical description of the ground-state...We study odd–even high-order harmonic generation（HHG） from oriented asymmetric molecules He H2＋numerically and analytically. The variational method is used to improve the analytical description of the ground-state wave function for the asymmetric system, with which the ground-state-continuum-state transition dipole is evaluated. The comparison between the odd–even HHG spectra and the improved dipoles allows us to identify and clarify the complex generation mechanism of odd–even harmonics from asymmetric molecules, providing deep insights into the relation between the odd–even HHG and the asymmetric molecular orbital.展开更多
We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis re...We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis reveals that for both HD^＋ and HeH^2＋, the nuclear dipole acceleration can generate even harmonics, but it is three orders of magnitude lower than that of the electron. Hence, the electronic dipole acceleration dominates the harmonic generation. For HD^＋,the electronic dipole acceleration only contributes to the generation of odd harmonics, but for HeH^2＋it contributes to the generation of both odd and even harmonics. Besides, one concept of the broken degree of system-symmetry is proposed to explain the different odd-even property between the harmonic spectra of HD^＋ and HeH^2＋.展开更多
We experimentally and theoretically demonstrate that ＊~he property （odd or even） of generated harmonics can be selected by manipulating the macroscopic phase-matching conditions based on a three-color laser field. ...We experimentally and theoretically demonstrate that ＊~he property （odd or even） of generated harmonics can be selected by manipulating the macroscopic phase-matching conditions based on a three-color laser field. Only odd or even harmonics can be made dominant by changing the focal position and adjusting the gas pressure. These results indicate that the odd-even property of the generated harmonics can be controlled by using the mult i-color laser field with macroscopic phase-matching.展开更多
基金Project supported by the National Natural Science Foundation of China(Grants No.91750111)the Youth Foundation of Hebei Province Education Department,China(Grant No.QN2017028)+2 种基金the Fundamental Research Funds for Hebei GEO University,China(Grant No.BQ2017047)the Natural Science Foundation of Hebei Province,China(Grant No.A2015205161)the Fundamental Research Funds for the Central Universities,China(Grant No.SNNU.GK201801009)
文摘We study high-order harmonic generation（HHG） from multi-center asymmetric linear molecules numerically and analytically. Our simulations show that odd and even HHG spectra of the asymmetric multi-center system respond differently to the change of the molecular structure. Specifically, when the internuclear distances between these nuclei of the molecule have a small change, the odd spectra usually do not change basically, but the even spectra differ remarkably. Based on this phenomenon, a simple procedure is proposed to probe the positions of these nuclei with odd–even HHG. Our results shed light on attosecond probing of the structure of multi-center molecules using HHG.
文摘The dynamical invariant for a general time-dependent harmonic oscillator is constructed by making use of two linearly independent solutions to the classical equation of motion. In terms of this dynamical invariant we define the time-dependent creation and annihilation operators and relevantly introduce even and odd coherent states for time dependent harmonic oscillator. The mathematical and quantum statistical properties of these states are discussed in detail. The harmonic oscillator with periodically varying frequency is treated as a demonstration of our general approach.
基金Project supported by the National Natural Science Foundation of China(Grant No.11274090)the Fundamental Research Funds for the Central Universities,China(Grant No.SNNU.GK201403002)
文摘We study odd–even high-order harmonic generation（HHG） from oriented asymmetric molecules He H2＋numerically and analytically. The variational method is used to improve the analytical description of the ground-state wave function for the asymmetric system, with which the ground-state-continuum-state transition dipole is evaluated. The comparison between the odd–even HHG spectra and the improved dipoles allows us to identify and clarify the complex generation mechanism of odd–even harmonics from asymmetric molecules, providing deep insights into the relation between the odd–even HHG and the asymmetric molecular orbital.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404153,11135002,11475076,and 11405077)the Fundamental Research Funds for the Central Universities of China(Grants Nos.lzujbky-2016-29,lzujbky-2016-31,and lzujbky-2016-209)
文摘We calculated the harmonic spectra generated from the asymmetric molecules of HD^＋ and HeH^2＋. It is found that HD＋produces only odd harmonics, while HeH^2＋produces both odd and even harmonics. Further analysis reveals that for both HD^＋ and HeH^2＋, the nuclear dipole acceleration can generate even harmonics, but it is three orders of magnitude lower than that of the electron. Hence, the electronic dipole acceleration dominates the harmonic generation. For HD^＋,the electronic dipole acceleration only contributes to the generation of odd harmonics, but for HeH^2＋it contributes to the generation of both odd and even harmonics. Besides, one concept of the broken degree of system-symmetry is proposed to explain the different odd-even property between the harmonic spectra of HD^＋ and HeH^2＋.
基金supported by the National Natural Science Foundation of China(Nos.11127901,6122106460921004,11134010,11227902,11222439,11274325,61108012,and 11474223)the National 973 Program(No.2011CB808103)+1 种基金the Natural Science Foundation of Zhejiang(No.LY14F050008)the Open Fund of the State Key Laboratory of High Field Laser Physics
文摘We experimentally and theoretically demonstrate that ＊~he property （odd or even） of generated harmonics can be selected by manipulating the macroscopic phase-matching conditions based on a three-color laser field. Only odd or even harmonics can be made dominant by changing the focal position and adjusting the gas pressure. These results indicate that the odd-even property of the generated harmonics can be controlled by using the mult i-color laser field with macroscopic phase-matching.
