Non-Markovian Effects in Far-Wing Light Scattering

Masaki Aihara

Stefano Cavalieri, Milva Celli

D. I. Mash, В. В. Морозов, V. S. Starunov +1 more

P. Thomann, Keith R. Burnett, J. Cooper

An absorption (and/or emission) event which takes place during a strong collision is called a 'correlated event'. It is discussed how correlated events affect the far red wing depolarization of fluorescence. Attention is given to an atomic vapor which is irradiated by linearly polarized light of a frequency on the red side of the resonance line. Two limiting cases are considered, corresponding to excitation in the impact region and in the quasi-static wing. In the quasi-static wing, absorption of a photon followed by fluorescence (rather than Rayleigh scattering), occurs mostly during a collision. Correlated events dominate the scattering process. Expressions derived for the polarization of the fluorescent light are applied to far red wing depolarization. It is found that the polarization of the fluorescent light does not go to zero in the far wing, but depends crucially on the detailed nature of the anisotropy in the long-range part of the interatomic potential.

Michio Hama, Masaki Aihara

We present a theoretical work on non-Markovian effects in the time-resolved spectrum (TRS) of resonant light scattering caused by a short pulse excitation. It is found that when the off-resonance frequency becomes comparable or greater than the inverse of the reservoir correlation time ${\ensuremath{\tau}}_{c}$, the finiteness of ${\ensuremath{\tau}}_{c}$ reduces the luminescencelike component which is energetically and temporally uncorrelated with incident radiation. It is emphasized that this non-Markovian effect in TRS is essential for obtaining a full understanding of the resonant light scattering phenomena.

P. Thomann, Keith R. Burnett, J. Cooper

Theory shows that to explain the polarization of light collisionally redistributed from the far line wings of an atomic transition, one must consider correlated events in which absorption during a collision, and propagation to the final Zeeman-state superposition at the end of the collision is important. Polarizations of up to about 40% have been measured in the far line wings, substantially confirming this prediction, and showing that scattering experiments cannot just be characterized by simple absorption or emission profiles.