Coherent Control of Stationary Light Pulses 1

We present a detailed analysis of the recently demonstrated technique to generate quasi-stationary pulses of light [M. Bajcsy et al., Nature (London) 426, 638 (2003)] based on electromagnetically induced transparency. We show that the use of counterpropagating control fields to retrieve a light pulse, previously stored in a collective atomic Raman excitation, leads to quasi-stationary light field that undergoes a slow diffusive spread. The underlying physics of this process is identified as pulse matching of probe and control fields. We then show that spatially modulated controlfield amplitudes allow us to coherently manipulate and compress the spatial shape of the stationary light pulse. These techniques can provide valuable tools for quantum nonlinear optics and quantum information processing.