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

Abstract

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.