Journal of Optoelectronics·laser

Effects of relative carrier-envelope phase on pulse characteristics in a Ξ-type medium

Fan Xi-jun

Published Jan 1, 2010• 0 citations

Abstract

In the cases of one-photon resonance and complete non-resonance, the effects of the relative carrier-envelope phase(RCEP) φ on pulse form and spectra characteristics of two-color ultrashort laser pulses in a Ξ-type three-level atomic medium are investigated by using numerical simulation.The results show that in the single-photon resonance case the RCEP has evident control role of profile and spectral characteristic of the two-color pulses.The RCEP can decide the amplitude, propagating velocity,pulse splitting case and the number of sub-pulses.When φ=0,the pulse does not split, and the shape and intensity of the pulse keep basically unchanged during the process of propagation.In the case of complete non-resonance, the pulse splitting doesn′t arise again, and the supercontinuum with frequency range much larger than that in the one-photon case can be obtained.Although the effects of RCEP on pulse shape and spectral property are not as strong as those in the one-photon resonance case, varying φ can still make frequency range and intensity distribution at different frequencies vary obviously.When φ=0, the supercontinuum with wider spectral range, better continuity and stronger intensity of high frequency components can be obtained.

Related papers

RCEP Modulation on Evolution of Two-color Femtosecond Pulses and Spectrum in a Dense V-type Medium

Fan Xi-jun

In one-photon resonance and detuning cases,effect of relative carrier-envelope phase(RCEP) on evolution of two-color sech-type femtosecond pulses and spectrum in a dense V-type three-level atomic medium is investigated with full Maxwell-Bloch equations.Modulation of RCEP on pulse shape and spectral property of two-color pulses in detuning case is more evident than that in single-photon resonance case.And in detuning case we get spectrum broadening much greater than that in resonance case.Supercontinuum with the highest frequency of 18 times of incident frequency appears.

Jisuan wuliJan 1, 20110 citations

Relative carrier—envelope phase dependence of resonant propagation of two-colour femtosecond pulses in V-type atomic medium

Xia Tan, Zhendong Wang, Lei Wang +1 more

Using numerical solution of the full Maxwell–Bloch equations, which is obtained by the finite-difference time-domain method and the iterative predictor–corrector method, we investigate the modulation effect of relative carrier–envelope phase (hereinafter referred to as the relative phase) on resonant propagation of two-colour femtosecond ultrashort laser pulses in a V-type three-level atomic medium. It is found that the pulse splitting occurs for a smaller value of relative phase; when the value of relative phase increases to a certain value, only the variation of pulse shape is present and the pulse splitting does not occur any more; moreover, when the value of relative phase is smaller, the pulse group velocity is larger. The relative phase also has an obvious effect on population and spectral property. Different population transfers can be realized by adjusting the value of relative phase. Generally speaking, for the pulses with smaller areas their spectral strengths and frequency ranges decrease obviously with the value of relative phase increasing; for the pulses with larger areas, with value of the relative phase increasing, their spectral strengths decrease remarkably but the relative strengths of the higher frequency components increase significantly, while the spectral frequency range is not varied evidently.

Chinese Physics BJun 1, 20101 citation

Effects of Carrier-envelope Phase on Few-cycle Ultrashort Laser Pulses Propagation in V-type Medium

Chengqiang Zhang

By solving the full Maxwell-Bloch equations,the effects of the carrier-envelope phase(CEP)on pulse propagating and spectra characteristics of few-cycle ultra short laser pulses in a dense V type three-level atomic medium are investigated.The results show that the carrier propagation and spectrum evolution of the pulse are sensitive to its CEP and the phase sensitivity is more obvious for larger area pulse.The CEP can affect the amplitude,propagating velocity and pulse splitting case.Moreover,under the same condition,the pulse spectra are affected by the initial carrier-envelope phases due to the different coherence effect,which don't induce obvious changes of higher spectral components.When,the super continuum with wider spectral range and better continuity of high frequency components can be obtained.

Journal of Weifang UniversityJan 1, 20110 citations

Effect of carrier envelope phase on propagation of femtosecond chirped Gaussian laser pulse in a dense three-level Λ-type atomic medium

Zhendong Wang

By the numerical analyzing and simulation, we investigate effect of carrier envelope phase on propagation of femtosecond chirped Gaussian laser pulse in a dense three-level Λ-type atomic medium. It is shown that, when the small area 2π negative chirped pulses (or the 2π positive chirped pulses) with different value of initial carrier envelope phase φ0 propagate in the medium, splitting don’t occur and the chirped pulses evolve gradually to approximate normal Gaussian pulses with equal amplitude and group velocity, and the phase differences between them remain the same as the case of initial input pulses. When the 4π negative chirped pulses with different φ0 propagate in the medium, the pulses will split into at least two sub-pulses and the amplitude of the first sub-pulse is far more than the second sub-pulse; These first sub-pulses have equal amplitudes and propagating with equal group velocity in the medium, and the phase differences between these first sub-pulses remain the same as the case of initial input pulses; The amplitudes of these second sub-pulses are not equal and don’t change monotonously with linearly increasing of φ0 but take on a invert S-shaped pattern, and the phase differences between these second sub-pulses are different. The case of 4π positive chirped pulses is similar to the case of 4π negative chirped pulses, but the amplitudes of these second sub-pulses split off from the 4π positive chirped pulses have no obvious changes compared with the case of 4π negative chirped pulses.

Oct 10, 20200 citations

Spectral properties of femtosecond chirped Gaussian pulse propagating in a dense three-level Λ-type atomic medium

Zhendong Wang, Zhongbo Liu, Ying Liang +2 more

It is shown that, variation of the sign and size of the chirp coefficient (C) of the pulse has considerable effect on spectral properties of the pulse and the effect is closely relative to size of the pulse area. When the pulse with smaller area, 2π pulse, propagates in the medium, pulse splitting doesn't occur and the pulse evolves gradually to an approximate normal Gaussian pulse (C=0); new high frequency component doesn't basically appear; with increasing value of C, oscillation amplitude of blue shift and red shift components increases and blue shift component oscillates more severely; moreover, the strength of the spectral component near the central frequency decreases considerably but the strength of blue shift component increases obviously. When the 4π pulse propagates in the medium, the pulse will split into sub-pulses with different numbers and shapes, new high frequency component can be produced, but the strength of the high frequency component is smaller; similar to the case of 2π pulse, blue shift component oscillates more severely; in addition, the strength of the spectral component with higher frequency decreases evidently with increasing value of C. When the pulse with larger area, 8π pulse, propagates in the medium, the pulse splitting is similar to that in the 4π pulse case, but supercontinuum spectrum with larger strength, higher frequency and wider frequency range than that in the 4π pulse case can be obtained; varying the sign and size of C can not produce new high frequency component, but can change strength of different frequency components in the spectrum, thus can get high frequency components with higher strength

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEOct 6, 20102 citations

Effects of Pulse Width on Ultrashort Pulse and Spectrum and Their CEP-dependence in a V-type Dense Medium

Fan Xi-jun

Effects of pulse width on ultrashort laser pulse and spectrum and their carrier-envelope phase(CEP) dependence in a dense V-type three-level atomic medium are investigated with numerical solutions of a full Maxwell-Bloch equation without slowly varying envelope and rotating wave approximations.It is shown that: As pulse width is small,pulse splitting number is less,spectrum is wide,high-frequency part of the spectrum is significant,CEP has great effect on pulse and spectrum,particularly effect on time interval between sub-pulses and strength of high-frequency part is more obvious;As pulse width increasing,pulse splitting number increases,width of spectrum narrows and high-frequency part of the spectrum decreases gradually,effect of CEP on pulse and spectrum weakens gradually.

Jisuan wuliJan 1, 20110 citations