All-optical light confinement in dynamic cavities

We show how to realize in a cold atomic sample a dynamic magneto-optically controlled cavity in
which a slow-light pulse can be confined and released on demand. The probe optical pulse is retrieved
from the atomic spin coherence initially stored within the cavity and is subsequently confined there
subject to a slow-light regime with little loss and diffusion for time intervals as long as a few hundred
microseconds before being extracted from either side of the cavity. Our proof-of-principle scheme
illustrates the underlying physics of this new mechanism for coherent light confinement and manipulation
in cold atoms. This may ease the realization of nonlinear interactions between weak light pulses where
strong atom-photon interactions are required for quantum information processing.