Under the condition of combined effects of group-velocity dispersion and self phase modulation, the step Fourier method is used to simulate the propagation of initial chirped super Gaussian pulses inside fiber. The in...Under the condition of combined effects of group-velocity dispersion and self phase modulation, the step Fourier method is used to simulate the propagation of initial chirped super Gaussian pulses inside fiber. The initial chirp influences the shapes of super Gaussian pulses in propagation process, and positive and negative chirps have different effects. For the existing of initial chirp, the splits 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 their propagation distance. Even if | C | increases to 3.5, their shapes are also good. Most energy of pulse is still at the middle parts. These results show that, for the initial chirped super Gaussian pulses, the influence of initial chirp will be decreased by increasing the intensity of pulses. This will be of benefit to optical communication.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
Relationship between the initial chirp of super-Gaussian pulse and dispersion and nonlinearity effects of a single-mode fiber in the optical communication system using midway optical phase conjugation is analyzed. The...Relationship between the initial chirp of super-Gaussian pulse and dispersion and nonlinearity effects of a single-mode fiber in the optical communication system using midway optical phase conjugation is analyzed. The results of numerical simulations are useful for improving compensation for pulse distortion.展开更多
文摘Under the condition of combined effects of group-velocity dispersion and self phase modulation, the step Fourier method is used to simulate the propagation of initial chirped super Gaussian pulses inside fiber. The initial chirp influences the shapes of super Gaussian pulses in propagation process, and positive and negative chirps have different effects. For the existing of initial chirp, the splits 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 their propagation distance. Even if | C | increases to 3.5, their shapes are also good. Most energy of pulse is still at the middle parts. These results show that, for the initial chirped super Gaussian pulses, the influence of initial chirp will be decreased by increasing the intensity of pulses. This will be of benefit to optical communication.
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.
文摘Relationship between the initial chirp of super-Gaussian pulse and dispersion and nonlinearity effects of a single-mode fiber in the optical communication system using midway optical phase conjugation is analyzed. The results of numerical simulations are useful for improving compensation for pulse distortion.
