Diffusion of resonance radiation in an infinite medium when there is absorption in the continuum

В. И. Бородулин

Yu. I. Geller, D. E. Sovkov, A. T. Hakim’yanov

Specific features of the propagation of light pulses with frequency lying in the range of autoionization resonances of the medium are analyzed. It is shown that the interference nature of the autoionization spectra makes it possible to combine a strong frequency dispersion of the refractive index with small absorption when the radiation frequency approaches the spectral range of the "transparency window" of an isolated resonance or of a series of overlapped autoionization resonances. This allows one to control the time delay of the pulses and their group velocity. Depending on the parameters of the medium, the pulse group velocity may be maximally reduced by a factor of 10 4 –10 5 .

S. Villalba, H. Failache, Athanasios Laliotis +3 more

We studied resonant laser interaction with Rb atoms confined to the interstitial cavities of a random porous glass. Due to diffusive light propagation, the effect of atomic absorption on the light scattered by the sample is almost entirely compensated by atomic fluorescence at low atomic densities. For higher densities, radiation trapping increases the probability of non-radiative decay via atom-wall collisions. A simple connection of the fluorescence/absorption yield to the sample porosity is given.

Yu. K. Zemtsov, A. Yu. Sechin, А. Н. Старостин

RBT Black

Diffusely reflected and transmitted spectral line profiles are calculated for uniform noncoherently scattering media onto which radiation of frequency near that of a resonance line of the medium is incident. Profiles are calculated for incident light that is either collimated or unifQrmly diffused and that is either monochromatic, or of uniform frequency distribution, or contains an absorption line centred on the resonance line under discussion. Spectral lines generated by uniformly excited media are also calculated.

Yu. A. Vdovin, V. M. Ermachenko