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
We investigate theoretically the ionization properties of the valence electron for the alkali metal atom Na in an intense pulsed laser field by solving numerically the time-dependent Schrodinger equation with an accur...We investigate theoretically the ionization properties of the valence electron for the alkali metal atom Na in an intense pulsed laser field by solving numerically the time-dependent Schrodinger equation with an accurate l-dependent model potential.By calculating the variations of the ionization probabilities with laser peak intensity for wavelengths ranging from 200 nm to 600 nm,our results present a dynamic stabilization trend for the Na atom initially in its ground state（3 s） and the excited states（3 p and 4 s） exposed to an intense pulsed laser field.Especially a clear ＂window＂ of dynamic stabilization at lower laser intensities and longer wavelengths for the initial state 4 s（the second excited state） is found.By analyzing the time-dependent population distributions of the valence electron in the bound states with the different values of principal quantum number n and orbital quantum number l,we can attribute the dynamic stabilization to the periodic population in the low-excited states since the valence electron oscillates rapidly between the lowly excited states and the continuum states.展开更多
We present the long-term stability of the integrating sphere cold atom clock（ISCAC） and analyze its systematic limitations. The relative frequency instability of 2.6 × 10-15 is reached for an averaging time of ...We present the long-term stability of the integrating sphere cold atom clock（ISCAC） and analyze its systematic limitations. The relative frequency instability of 2.6 × 10-15 is reached for an averaging time of 2 ×105 s. The second-order Zeeman effect and the cavity pulling effect in ISCAC, which would induce the frequency drift from the clock transition, are analyzed. The analytical and experimental results indicate that the cavity pulling effect is the main contribution to the long-term frequency instability of the ISCAC. Further technical improvements to the microwave cavity are also discussed.展开更多
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 supported by the National Natural Science Foundation of China(Grant Nos.11465016,11664035,and 11764038)
文摘We investigate theoretically the ionization properties of the valence electron for the alkali metal atom Na in an intense pulsed laser field by solving numerically the time-dependent Schrodinger equation with an accurate l-dependent model potential.By calculating the variations of the ionization probabilities with laser peak intensity for wavelengths ranging from 200 nm to 600 nm,our results present a dynamic stabilization trend for the Na atom initially in its ground state（3 s） and the excited states（3 p and 4 s） exposed to an intense pulsed laser field.Especially a clear ＂window＂ of dynamic stabilization at lower laser intensities and longer wavelengths for the initial state 4 s（the second excited state） is found.By analyzing the time-dependent population distributions of the valence electron in the bound states with the different values of principal quantum number n and orbital quantum number l,we can attribute the dynamic stabilization to the periodic population in the low-excited states since the valence electron oscillates rapidly between the lowly excited states and the continuum states.
基金supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe National Natural Science Foundation of China (Nos. 61727821 and 11604353)
文摘We present the long-term stability of the integrating sphere cold atom clock（ISCAC） and analyze its systematic limitations. The relative frequency instability of 2.6 × 10-15 is reached for an averaging time of 2 ×105 s. The second-order Zeeman effect and the cavity pulling effect in ISCAC, which would induce the frequency drift from the clock transition, are analyzed. The analytical and experimental results indicate that the cavity pulling effect is the main contribution to the long-term frequency instability of the ISCAC. Further technical improvements to the microwave cavity are also discussed.
