Nonlinear propagation of four components with different polarizations and frequencies in a single optical pulse by using a five-level atomic system

We investigate the nonlinear propagation of four components with different circular polarization states and frequencies in a single optical pulse, occurring in a resonant M-type, five-level atomic system via electromagnetically induced transparency. We show that these four components in the system are coupled to each other due to the symmetry of the level configuration. We demonstrate that, for long probe pulses, self-trapped polarization states with a trapped phase can be obtained. In addition, a polarization rotor can be realized through a polarization instability, which can be working at a very low light level and may have a practical application. For short probe pulses, four-component optical solitons can be generated in the system, which have a very slow propagating velocity and very low generation power. The results reported here may have potential applications in optical information processing and transmission.