Efficient light storage with reduced energy loss via nonlinear compensation in rubidium vapor

We report an experimental demonstration of efficient light storage based on a modified technique of electromagnetically induced transparency in hot rubidium vapor. By introducing an auxiliary pump field to go beyond the -type configuration, we find that the undesired four-wave mixing can be greatly suppressed to result in sufficiently reduced energy loss of a probe pulse. The light storage efficiency can be as high as ~80% within the storage time of 100 ns with the pump field applied, which is almost 6 times larger than that in the absence of the pump field. We may also amend the light storage efficiency in a linear way by increasing the optical depth of our atomic vapor even without saturation effect. We obtain, in fact, an amplified probe pulse via Raman gain during light storage and retrieval, which should have practical applications in classical and quantum information processing.