By employing stimulated Raman backscattering in a plasma, information carried by a laser pulse can be captured in the form of a very slowly propagating plasma wave that persists for a time long compared with the pulse duration. If the plasma is then probed with a short laser pulse, the information stored in the plasma wave can be retrieved in a second scattered electromagnetic wave. The recording and retrieving processes can conserve robustly the pulse shape, thus enabling the recording and retrieving with fidelity of information stored in optical signals.

• Received 2 November 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.165001