We investigate the formation and propagation of vector vortex solitons (VS) and unipolar soliton (US) in a cold atomic gas with Bessel lattices (BLs). The system we consider is a cold, coherent atomic gas with a tripod or multipod level configuration. Dueing to the giant enhancement of Kerr nonlinearity contributed by electromagnetically induced transparency (EIT), a vector weak vortex soliton can be effectively formed with ultraslow propagating velocity. Furthermore, we demonstrate that the characteristics of 2D VS and US can be controlled and manipulated via adjusting BLs. The results predicted here may be used to design all-optical switching at very low light level.
We propose a scheme to realize storage and retrieval of two-component optical soliton in a coherent atomic system. The system under consideration is a cold, lifetime-broadened four-level atomic gas with a tripod configuration working at the condition of double electromagnetically induced transparency. We show that due to the existence of two dark states, the optical absorption of the probe pulse can be largely reduced. In addition, the two orthogonal polarization components of the probe pulse with a form of vector optical soliton cannot only be slowed down substantially but also be stored and retrieved robustly by switching a control laser field off and on. We also show that it is possible to achieve a memory of
N-component optical soliton by using the
N dark states in a
(N+1)-pod system
(N>2). The results reported here may have promise in applications for light information processing in a weak nonlinear regime.
Realizing vector spatiotemporal solitons that are stable in high dimensions is a long-standing goal in the study of nonlinear optical physics. Here, a scheme is proposed to generate three-dimensional (3D) vector spatiotemporal solitons in a cold atomic system with linear and nonlinear parity-time (PT) potentials by utilizing electromagnetically induced transparency (EIT). We investigate the existence and stability of these vector 3D semilunar solitons (SSs) and vortex solitons (VSs) supported by the linear and nonlinear PT potentials. The results show that these solitons have extremely low generation power and very slow propagation velocity and can stably propagate with constant total energy in this system. The frontal head-on collisions of two vector solitons feature quasi-elastic collisions. The dynamics characteristics of these solitons depend on the linear and nonlinear PT-symmetric potential parameters, in particular, the imaginary part of PT potentials. Our study provides a new route for manipulating high-dimensional nonlinear vector optical signals via the controlled optical linear and nonlinear potentials in cold atomic gases.