Under the condition of combined effects of group--velocitydispersion and self- phase modulation, the step Fourier method isused to simulate the propagation of initial chirped super-Gaussianpulses inside fiber. The ini...Under the condition of combined effects of group--velocitydispersion and self- phase modulation, the step Fourier method isused to simulate the propagation of initial chirped super-Gaussianpulses inside fiber. The initial chirp influences the shapes of superGaussian pulses in propagation process, and positive and negativechirps have different effects. For the existing of initial chirp, thesplits of pulses and the spreading speed move ahead and increase.When the amplitude of super-Gaussian pulses increases by 1.4 times,in the range of │C│<1.5, pulses can keep good shapes along theirpropagation distance.展开更多
The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-G...The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-Gaussian laser pulse and a time-delayed terahertz half-cycle pulse(THz HCP). It is shown that the degree of field-free orientation can be doubled by the combined pulse with respect to the super-Gaussian pulse or THz HCP alone. Moreover, different laser intensities, carrier envelop phases, shape parameters, and time delays have great influence on the positive and negative orientations, with other conditions unchanged. Furthermore, it is indicated that the maximum degree and direction of molecular orientation can be precisely controlled by half of the duration of the super-Gaussian pulse. Finally, by adjusting the laser parameters of the super-Gaussian laser pulse and THz HCP, the optimal results of negative orientation and corresponding rotational populations are obtained at different temperatures of the molecular system.展开更多
Using time-dependent multilevel approach （TDML）, this paper studies the dynamics of coherent control of Rydberg lithium atoms and demonstrates that Rydberg lithium atoms can be transferred to states of higher princi...Using time-dependent multilevel approach （TDML）, this paper studies the dynamics of coherent control of Rydberg lithium atoms and demonstrates that Rydberg lithium atoms can be transferred to states of higher principal quantum number by exposing them to specially designed frequency-chirped laser pulses. The population transfer from n=70 to n=75 states of lithium atoms with efficiency more than 90% is achieved by means of the sequential adiabatic rapid passages. The results agree well with the experimental ones and show that the coherent control of the population transfer from the lower n to the higher n states can be accomplished by the optimization of the chirping parameters and the intensity of laser field.展开更多
文摘Under the condition of combined effects of group--velocitydispersion and self- phase modulation, the step Fourier method isused to simulate the propagation of initial chirped super-Gaussianpulses inside fiber. The initial chirp influences the shapes of superGaussian pulses in propagation process, and positive and negativechirps have different effects. For the existing of initial chirp, thesplits of pulses and the spreading speed move ahead and increase.When the amplitude of super-Gaussian pulses increases by 1.4 times,in the range of │C│<1.5, pulses can keep good shapes along theirpropagation distance.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674198 and 11874241)the Taishan Scholar Project of Shandong Province,China
文摘The molecular orientation created by laser fields is important for steering chemical reactions. In this paper, we propose a theoretical scheme to manipulate field-free molecular orientation by using an intense super-Gaussian laser pulse and a time-delayed terahertz half-cycle pulse(THz HCP). It is shown that the degree of field-free orientation can be doubled by the combined pulse with respect to the super-Gaussian pulse or THz HCP alone. Moreover, different laser intensities, carrier envelop phases, shape parameters, and time delays have great influence on the positive and negative orientations, with other conditions unchanged. Furthermore, it is indicated that the maximum degree and direction of molecular orientation can be precisely controlled by half of the duration of the super-Gaussian pulse. Finally, by adjusting the laser parameters of the super-Gaussian laser pulse and THz HCP, the optimal results of negative orientation and corresponding rotational populations are obtained at different temperatures of the molecular system.
基金Project supported by the National Natural Science Foundation of China(Grant No.10774039)the Basic Research Program of Education Bureau of Henan Province of China(Grant No.072300410130)
文摘Using time-dependent multilevel approach （TDML）, this paper studies the dynamics of coherent control of Rydberg lithium atoms and demonstrates that Rydberg lithium atoms can be transferred to states of higher principal quantum number by exposing them to specially designed frequency-chirped laser pulses. The population transfer from n=70 to n=75 states of lithium atoms with efficiency more than 90% is achieved by means of the sequential adiabatic rapid passages. The results agree well with the experimental ones and show that the coherent control of the population transfer from the lower n to the higher n states can be accomplished by the optimization of the chirping parameters and the intensity of laser field.
