44,753 research outputs found
Storage of light: A useful concept?
We show both analytically and numerically that photons from a probe pulse are
not stored in several recent experiments. Rather, they are absorbed to produce
a two-photon excitation. More importantly, when an identical coupling pulse is
re-injected into the medium, we show that the regenerated optical field has a
pulse width that is very different from the original probe field. It is
therefore, not a faithful copy of the original probe pulse.Comment: 5 pages, 3 figures. Correct LaTEX listings of reference
Collective atomic recoil motion in short-pulse multi-matter-optical wave mixing
An analytical perturbation theory of short-pulse, matter-wave superradiant
scatterings is presented. We show that Bragg resonant enhancement is
incapacitated and both positive and negative order scatterings contribute
equally. We further show that propagation gain is small and scattering events
primarily occur at the end of the condensate where the generated field has
maximum strength, thereby explaining the apparent ``asymmetry" in the scattered
components with respect to the condensate center. In addition, the generated
field travels near the speed of light in a vacuum, resulting in significant
spontaneous emission when the one-photon detuning is not sufficiently large.
Finally, we show that when the excitation rate increases, the generated-field
front-edge-steepening and peak forward-shifting effects are due to depletion of
the ground state matter wave.Comment: This manuscript was submitted for publication in Nov., 200
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