Storage and retrieval of optical pulses using a two-color optical memory

The complete waveforms of 1.4 mus optical signal pulses are delayed and stored using a coherently prepared warm Rb vapor, and then recovered up to 500 mus later (with a factor of 2 temporal pulse broadening). Mediated by four-wave mixing, frequency-shifted idler pulses are generated, and then stored and retrieved simultaneously with the signal pulses. The intensities of the retrieved pulses depend linearly on the intensity of the retrieving coupling beam.