Ultraslow temporal vector optical solitons in a cold five-state atomic medium under Raman excitation

Abstract

We theoretically investigate the formation of ultraslow temporal vector optical solitons in a lifetime-broadened five-state atomic system under Raman excitation. By analysing the interaction between the atomic system and two strong, linear-polarized continuous wave control fields and a weak, linear-polarized pulsed signal field, having two orthogonally polarized components, we find that the Maxwell equations of describing the propagation of two orthogonal polarization components can evolve into two coupled nonlinear Schrödinger equations, which admit solutions describing vector solitons, including bright–bright, bright–dark, dark–bright and dark–dark vector solitons with ultraslow group velocity. More importantly, the Manakov temporal vector solitons can be easily realized in our system by adjusting the corresponding parameters such as the Rabi frequencies of the control fields, one- and two-photon detunings. The unique features of the two coupled nonlinear Schrödinger equations are also discussed.