Propagation Of Few-cycle Laser Pulse Research Articles

Shaping of few-cycle laser pulses via a subwavelength structure

We theoretically investigate the propagation of few-cycle laser pulses in resonant two-level dense media with a subwavelength structure, which is described by the full Maxwell—Bloch equations without the frame of slowly varying envelope and rotating wave approximations. The input pulses can be shaped into shorter ones with a single or less than one optical cycle. The effect of the parameters of the subwavelength structure and laser pulses is studied. Our study shows that the media with a subwavelength structure can significantly shape the few-cycle pulses into a subcycle pulse, even for the case of chirp pulses as input fields. This suggests that such subwavelength structures have potential application in the shaping of few-cycle laser pulses.

Transparent propagation of few-cycle laser pulses with arbitrary intensity in double-lambda atomic systems

A numerical study is reported of the transparent propagation of few-cycle laser pulses with arbitrary intensity. The phenomenon is based on the preparation of steady maximum coherent superposition state of the lower two levels in double-lambda atomic systems. The transparency of the few-cycle pulse is sensitive to its parameters such as the arriving time and relative phase. The advantages of the method are discussed.

Population difference study of few-cycle laser pulse propagating in near-resonant two-level atom medium

We have theoretically studied the propagation of few-cycle laser pulse in near-resonant two-level atom medium by solving Maxwell-Bloch equations with a predictor-corrector finite-difference time-domain method. Hyperbolic secant pulses with area 2π, 4π and 6π are adopted as the initial inputs. For large pulse area, the carrier-wave Rabi flopping occurs in the faster split 2π pulse and causes spectra broadening which subsequently increases the induced population difference. Combined with the contribution of periodically varying carrier-envelop phase, the maximum of population difference gives rise to an interesting phenomenon.

Propagation of few-cycle laser pulses through a linear gas medium

We investigate the ultrashort pulse propagation through a linear gas medium by direct solution of the wave equation beyond the often used lowest orders of the dispersion approximation and the assumption of a slowly varying envelope. The dispersion effects and the effective absorption of the pulse energy by the medium are shown to result in a strong dispersive broadening of the initial pulse in the time and space domains. New features of the polarization response of the medium resulting from essentially nonadiabatic ramps of the pulse envelope are found. The possibility of using the two-pulse experimental scheme to partly compensate for the dispersion is discussed.