Multiple scattering of photons by atomic hyperfine multiplets

Abstract

Mesoscopic interference effects in multiple scattering of photons depend crucially on the internal structure of the scatterers. In the present article, we develop the analytical theory of multiple photon scattering by cold atoms with arbitrary internal hyperfine multiplets. For a specific application, we calculate the enhancement factor of elastic coherent backscattering as a function of detuning from an entire hyperfine multiplet of neighboring resonances that cannot be considered isolated. Our theory permits to understand why atoms behave differently from classical Rayleigh point-dipole scatterers, and how the classical description is recovered for larger but still microscopic objects like molecules or clusters.

Direct measurement of the Wigner time delay for the scattering of light by a single atom

“…Later, F. T. Smith pointed out that this so-called Wigner delay is the lifetime of a resonant state excited during the scattering [2], therefore being largest at resonance. Since its derivation, the Wigner delay has been used as an important parameter in the problem of near-resonant scattering in dense media, as it governs the transport of energy [3][4][5][6][7].…”

Weak localization of light in hot atomic vapors

“…In light scattering by cold atoms, an important physical ingredient affecting weak localization is the quantum level structure of the atomic scatterers. In general, the quantum selection rules of a given atomic transition give rise to an imbalance between time-reversed scattering trajectories, which eventually reduces the CBS peak contrast [3,[26][27][28]. The same phenomenon is expected to occur in a hot atomic vapor, and therefore should be accounted for.…”

Coherent Transport of Light in Cold Atoms

“…This may be an indication of the effect of other accessible excited states in the hyperfine multiplet. 32,33 Although far detuned, the corresponding transitions can yield interference effects which affect the enhancement factor.…”