Nonlinear resonance scattering of polarized light by an atom

M. Ya. Agre, Л. П. Рапопорт, M. E. Alferieff

Nikolai B. Delone, В. П. Крайнов

Some typical resonance nonlinear-optics phenomena taking place when light interacts with atoms are considered. The multitude of such phenomena reduces to scattering of the perturbing light, perturbation of the atomic spectrum, excitation of an atom and its ionization. In all these cases the investigations are carried out using the simplest model—an isolated atom in a monochromatic external field. Such a model enables one to give an exact description of many elementary processes. On the other hand it is sufficiently realistic. A detailed investigation is carried out of resonance fluorescence, spontaneous Raman scattering, multiphoton excitation of atoms, resonance shifts and splitting of atomic levels and resonance lonication of atoms. The nature of these processes is investigated as a function of the intensity of the external field, its frequency, a specific atomic spectrum, the nature of polarization of the perturbing field, and the degree of its nonlinearity. The role played by the field of the electromagnetic vacuum is analyzed. Theoretical predictions are compared with the results of many experiments describing resonance processes of the interaction of an intense light field with atoms.

R. G. Olave, Aye Win, K. Kemp +5 more

A brief perspective on light scattering in dense and cold atomic rubidium is presented. We particularly focus on the influence of auxiliary applied fields on the system response to a weak and nearly resonant probe field. Auxiliary fields can strongly disturb light propagation; in addition to the steady state case, dynamically interesting effects appear clearly in both the time domain, and in the optical polarization dependence of the processes. Following a general introduction, two examples of features found in such studies are presented. These include nonlinear optical effects in (a) comparative studies of forward- and fluorescence-configuration scattering under combined excitation of a control and probe field, and (b) manipulation of the spatial structure of the optical response due to a light shifting strong applied field.

B. B. Averbukh, I. B. Averbukh

Давид Николаевич Клышко

Olivier Émile, Fabien Bretenaker, A. Le Floch

The recent technical advances in the creation of rapidly rotating light polarizations are shown to provide new tools to explore elastic and inelastic scattering phenomena. In the case of inelastic scattering, the light fluoresced by atoms or molecules coherently excited by a rapidly rotating linear polarization is expected to exhibit new resonances. Such resonances, due to the transfer of coherence from light to atoms or molecules, are theoretically studied and experimentally observed. They provide simple methods to probe atomic internal constants, such as energy level life-times. The analogy between those resonances and the Hanle effect suggests new experiments in atomic physics. In the case of elastic scattering such as the one encountered during propagation through a dense turbid medium, the rotating linear polarization is shown to be an ideal tool to extract the ballistic photons from the large background of diffused light. This permits to image tiny objects embedded in a dense turbid medium, with an experimental resolution similar to the one obtained in usual homogeneous optical system.