Superluminal Ultrasensitive Optical Gyroscope in an Inverted Double-Raman Lambda System

The probe field in an inverted double-Raman lambda atomic system experiences a gain along with a negative dispersion. We show in this talk how a critical negative dispersion can lead to a dramatic enhancement in the sensitivity to cavity length change --- induced by rotation, for example --- for a ring laser employing this gain. The critical anomalous dispersion enhances the lasing frequency shift by as much as five orders of magnitude when compared to a conventional ring laser with the same dimensions. We show how a careful selection of the experimental parameters, such as strengths of the two controlling fields, can lead to the critical dispersion of interest. We also describe how such a laser can be used to realize a superluminal ring laser gyroscope with highly enhanced sensitivity. Finally, we describe our experimental efforts toward realizing such a superluminal ring laser using a rubidium vapor cell and dual frequency Raman pumps.