Redistribution of light frequency by multiple scattering in a resonant atomic vapor
arXiv:1506.05683 · doi:10.1103/PhysRevA.91.053846
Abstract
The propagation of light in a resonant atomic vapor can \textit{a priori} be thought of as a multiple scattering process, in which each scattering event redistributes both the direction and the frequency of the photons. Particularly, the frequency redistribution may result in Lévy flights of photons, directly affecting the transport properties of light in a resonant atomic vapor and turning this propagation into a superdifusion process. Here, we report on a Monte-Carlo simulation developed to study the evolution of the spectrum of the light in a resonant thermal vapor. We observe the gradual change of the spectrum and its convergence towards a regime of Complete Frequency Redistribution as the number of scattering events increases. We also analyse the probability density function of the step length of photons between emissions and reabsorptions in the vapor, which governs the statistics of the light diffusion. We observe two different regime in the light transport: superdiffusive when the vapor is excited near the line center and normal diffusion for excitation far from the line center. The regime of Complete Frequency Redistribution is not reached for excitation far from resonance even after many absorption/reemission cycles due to correlations between emitted and absorbed frequencies.
arXiv comment23 pages, 11 figures
References in corpus (7)
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Cited by in corpus (6)
- Subradiance and radiation trapping in cold atoms
- Diffusing-Wave Spectroscopy of Cold Atoms in Ballistic Motion
- Temporal intensity correlation of light scattered by a hot atomic vapor
- Generation of ideal thermal light in warm atomic vapor
- Lévy flights of photons with infinite mean free path
- Two-photon excitation of rubidium atoms inside porous glass