Three-wave superluminal vector optical solitons in a seven-level atomic system

Abstract

We investigate generation of three-wave coupled superluminal vector optical solitons in an active-Raman-gain (ARG) seven-level atomic system. By solving the probability amplitude equations, the linear, nonlinear and dispersion of the optical properties are analyzed for the three probe fields, which show that the dispersion effects of the probe fields can be well balanced by self-phase and cross-phase modulation of the Kerr nonlinearities and the gain can be well suppressed under certain conditions. Therefore, three-wave coupled optical vector solitons with superluminal propagating group velocity can be formed in the system. Moreover, this atomic system allows the existence of various types of three-wave superluminal vector solitons by adjusting the system parameters. We also give real parameters of 87Rb atoms for generating three-wave superluminal vector solitons, which may provide reference for experiments.