399 research outputs found
Single-cell atomic quantum memory for light
Recent experiments demonstrating atomic quantum memory for light [B.
Julsgaard et al., Nature 432, 482 (2004)] involve two macroscopic samples of
atoms, each with opposite spin polarization. It is shown here that a single
atomic cell is enough for the memory function if the atoms are optically pumped
with suitable linearly polarized light, and quadratic Zeeman shift and/or ac
Stark shift are used to manipulate rotations of the quadratures. This should
enhance the performance of our quantum memory devices since less resources are
needed and losses of light in crossing different media boundaries are avoided.Comment: 6 pages, 2 figures, to be published in Phys. Rev.
Single-passage read-out of atomic quantum memory
A scheme for retrieving quantum information stored in collective atomic spin
systems onto optical pulses is presented. Two off-resonant light pulses cross
the atomic medium in two orthogonal directions and are interferometrically
recombined in such a way that one of the outputs carries most of the
information stored in the medium. In contrast to previous schemes our approach
requires neither multiple passes through the medium nor feedback on the light
after passing the sample which makes the scheme very efficient. The price for
that is some added noise which is however small enough for the method to beat
the classical limits.Comment: 8 pages, 2 figures, RevTeX
- …