| Laser pulse with a ultrashort duration and an extremely strong peak intensity exhibits extensive applications in physics, chemistry, biology and other interdisciplinary studies including femtochemistry, biophotonic imaging, and so on. When the ultrashort pulse containing only a few optical cycles, the carrier-envelope phase (CEP) will greatly affect the nonlinear processes of laser-matter interaction. Thus, it is of great meaningful to study the CEP dependent effects and subsequently develop technologies of controlling the CEP of ultrashort pulse in the modern optics. We use numerical simulation to study the CEP dependent effects and the propagation of few-cycle pulse in two or three levels system respectively. The main contents are as follows:(i). We investigate carrier-envelope-phase-dependent effects in cutoff region of the high-order harmonic generation(HHG) in a two-level atom system which is strongly driv-en by a few-cycle pulse. The evolution of adiabatic energies and HHG in cutoff region are studied in detail by using a Gaussian-shape pulses with two different CEPs,φ=0 andφ=π/2 as the incidence pulse. Numerical result shows that the generation of high harmonic is closely related with the variation of the incidence pulse. As in the "three step model", the HHG in the cutoff region in "two-level atom" is strongly dependent on the CEP of the few-cycle pulse.(ii). We theoretically investigate the CEP dependence of the electron tunneling of a few-cycle laser pulse in a coupled double-quantum-dot system. Via numerical simula-tions, we study the electron population of right quantum dot (QD) after the passing of the pulse as a function of the CEP. The results show that the electron tunneling in the coupled QDs is very sensitive to the CEP for the different parameters of the system, and these de-pendence are even greater than the CEP dependence of the bound-state atomic coherence and the quantum beats in cold atoms.(iii). We analyze the effect of near dipole-dipole (NDD) interaction on the propaga-tion of the soliton which generated by a 5fs pulse penetrates through resonant two-level dense media with a subwavelength structure. The local field effect caused by NDD inter- action in a dense medium will accelerate the group velocity of the gap soliton and make the frequency a small shift to the low frequency region, but has no effect on the transmit-ted soliton. If the atomic density is increased, the sub-cycle soliton will not be obtained for the reason that reflection on the interfaces of the atomic layers is enhanced. Therefore, it is reasonable to neglect the NDD effect on propagation in this model.(ⅳ). We propose the scheme of generate sub-cycle pulse by utilizing few-cycle pulse propagating in an three levels asymmetric coupled-quantum-well (CQW) nanostructure. The electric field profiles for 2πpulse can't reproduce the SIT propagating as expecta-tion but reduced multiple-cycle field oscillating with lower intensity, while 4πpulse can generate a well behaved sub-cycle pulse. Our scheme is a promising way to generate sub-cycle pulse for the flexibility in materials choice and structure design.Ultrafast optics is of rapid development in recent years. Our research is concentrated on the interaction of few-cycle pulse with bound states in a weak field region. We propose several schemes to measure the CEP of few-cycle pulse and to generate sub-cycle pulse, which will hopefully make some contributions to the future development of ultrafast optics.
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