Storage and Retrieval of Light Pulses in a Fast-Light Medium via Active Raman Gain

We propose a scheme to realize the storage and retrieval of light pulses in a fast-light medium via a mechanism of active Raman gain (ARG). The system under consideration is a four-level atomic gas interacting with three (pump, signal and control) laser fields. We show that a stable propagation of signal light pulses with superluminal velocity (i.e. fast-light pulses) is possible in such system through the ARG contributed by the pump field and the quantum interference effect induced by the control field. We further show that a robust storage and retrieval of light pulses in such fast-light medium can be implemented by switching on and off the pump and the control fields simultaneously. The results reported here may have potential applications for light information processing and transmission using fast-light media.