Marking slow light signals with fast optical precursors in the regime of electromagnetically induced transparency

摘要

In order to identify special information from a light pulse sequence, we propose a few viable schemes for marking a desired slow light signal with a fast optical precursor in a Λ-type and N-type atomic system. The fast optical precursor is characterized by transient beating patterns originating from the temporal discontinuity of the marking pulse at the sharp rising or falling edge. Compared with the schemes in the Λ system, the one in the N system has the advantage of flexibility in situations in which we are not the sender of the original probe signals. Besides, there is no disturbance to the probe signals nor an undesired main pulse coming from the marking field.