Frequency-chirped copropagating multiple-bit stimulated-echo storage and retrieval in Pr(3+):YAlO(3)

Using a frequency-chirped ring dye laser, we have stored and recalled as much as 48 bits of information with the copropagating stimulated-echo geometry on the (3)H(4)-(1)D(2) transition in Pr(3+):YAlO(3). Since the copropagating excitation scheme has all the excitation pulses spatially overlapping, this technique will be useful to the practical implementation of stimulated-echo memory because there is no need for alignment of beams. Our experiments also demonstrate that frequency chirping of the excitation pulses dramatically improves not only pulse-shape reproduction by the echo pulse but also the shot-to-shot stability of the amplitude of the recalled data.