Single Attosecond Pulse Generation From Synthesized Pulse With Longer Duration

Attosecond pulse may track the movement of electrons, observe the relaxation process of electron within atom or molecule.If we can understand deeply these process, it is helpful for development of new light source and the exploring of microscopic origin about serious. Also, a single attosecond pulse will be widely used in pump probe experiments in x-ray waveband.So the realization of an ultrashort pulse with attosecond pulse width is of important application value in ultrafast optics.However, it is shown that a 6 femosecond ultrashort pulse must be adopted if one wants to obtain a single attosecond pulse. Although 6 femosecond ultrashort pulse can be obtained in experiment, its phase is unstable and its peak intensity isn't high. And for a majority of laboratories, it is very difficult to realize. Based on this, in this paper we proposed a new method that a single attosecond pulse generation can be generated by using synthesized pulse with longer duration. This method overcomes the difficulty of traditional methods that phase is unstable and its peak intensity isn't high.In this paper, firstly, we solve numerically the time-dependent schrodinger equation by Crank-Nicolson method, and by wavelet transform for harmonics near the cutoff position, a single attosecond pulse can be obtained. The generation mechanism for this method also be given in detail in this paper. The combined pulse composed of a fundamental Ti:sapphire laser and its second harmonic.To obtain the best result for this method, we modulate the relative phase between two pulses on a large scale. As a result, we obtain a single 80 attosecond pulse. This result is of important guide significance in experiment.