Observation of giant group index in a multi-level Rb atomic medium at room temperature.

We report an experimental measurement of giant group index in the Rb atomic medium at room temperature via a four-level V-type scheme on the D line. Our experiment uses co-propagation configuration of probe and coupling lasers through an atomic sample. In this configuration, three sharp EIT windows with significant transparency depths are observed on the probe absorption spectrum.

Two-channel optical bistability and multistability in a degenerate four-level atomic medium under a static magnetic field.

In this paper, we study the formation of optical bistability (OB) and optical multistability (OM) in a degenerate four-level atomic system by an external magnetic field that is excited by a probe laser field, a coupling laser field and a signal laser field. The coupling field can cause electromagnetically induced transparency (EIT) for the probe field in the atomic medium, while the signal field and/or external magnetic field can switch between single-EIT and two-EIT regimes. Based on these properties, OB and OM effects can be formed at two different frequency regions of the probe field (two channels).

Controllable ultraslow optical solitons in a degenerated two-level atomic medium under EIT assisted by a magnetic field.

We proposed a simple model for generation of controllable ultraslow optical solitons of a weak probe laser light in a degenerated two-level atomic medium under electromagnetically induced transparency assisted by a magnetic field. It is shown that bright and dark optical solitons can be formed from a probe light with controllable ultraslow group velocities at a few m/s by tuning the strength of a coupling light and/or the magnetic field. In addition to the ultraslow velocity, the advantage of this model is to use a sole laser for delivering both pump and probe lights.