Low group velocity of light without an extra driving laser field

Cui Ni, X. J. Fan, Shufen Tian +3 more

The group velocity of the probe light pulse (GVPLP) propagating through an open Λ-type atomic system with a spontaneously generated coherence is investigated when the weak probe and strong driving light fields have different frequencies. It is found that adjusting the detuning or Rabi frequency of the probe light field can realize switching of the GVPLP from subluminal to superluminal. Changing the relative phase between the probe and driving light fields or atomic exit and injection rates can lead to GVPLP varying in a wider range, but cannot induce transformation of the property of the GVPLP. The absolute value of the GVPLP always increases with Rabi frequency of the driving light field increasing. For subluminal and superluminal propagation, the system always exhibits the probe absorption, and GVPLP is mainly determined by the slope of the steep dispersion.

Yu. M. Golubev, T. Yu. Golubeva, Yuri V. Rostovtsev +1 more

B. Macke, B. S�gard

Zhihua Peng

This paper reveals that the group velocity of a weak laser probe field can be manipulated by controlling the intensity of the driving field applied to a near-degenerate closed three-level V system.Such control can even cause the probe propagation to change from subluminal to superluminal.And the results mentioned above can be understood in terms of dressed states.

Mostafa Sahrai, H. Tajalli, Kishore T. Kapale +1 more

We demonstrate tunable control of the group velocity of a weak probe pulse from subluminal to superluminal. The model is an extended $\ensuremath{\Lambda}$-type system with two extra control fields and an extra energy level. Phase variation of one of the control fields imparts the tunability in the group velocity along with other interesting spectral behavior in the absorption spectrum.

Jingjuan Li, Xijun Fan, Shufen Tian +3 more