S. Balik

A scaling law for light scattering from dense and cold atomic ensembles

We calculate the differential cross-section of polarized light scattering from a cold and dense atomic ensemble. The regularities in the transformation of the cross-section when increasing the size of the atomic ensemble are analyzed numerically. We show that for typical experimental conditions, an approximate scaling law can be obtained. Very good agreement is found in a comparison with experimental data on the size dependence of a dense and cold cloud of 87Rb atoms.

Strong-field coherent backscattering of light in ultracold atomic 85Rb

We report experimental observations of polarization-dependent coherence loss occurring in strong-field multiple scattering of light in ultracold atomic 85Rb. A measure of coherence in multiple light scattering is the degree of contrast of the coherent backscattering enhancement from the vapour. For resonance saturation parameters up to 9, we see light-polarization-dependent modification of the backscattering enhancement, suggesting that inelastic atomic light scattering and dynamic atomic magnetization may play important roles in the multiple scattering process for 85Rb.

Alignment dynamics of slow light diffusion in ultracold atomic 85Rb

A combined experimental and theoretical investigation of time- and alignment-dependent propagation of light in an ultracold atomic gas of atomic {sup 85}Rb is reported. Coherences among the scattering amplitudes for light scattering off excited hyperfine levels produce strong variations of the light polarization in the vicinity of atomic resonance. Measurements are in excellent agreement with Monte Carlo simulations of the multiple scattering process.

Quadrature noise in light propagating through a cold 87Rb atomic gas

We report on the study of the noise properties of laser light propagating through a cold 87Rb atomic sample held in a magneto-optical trap. The laser is tuned around the F g  = 2 → F e  = 1, 2 D1 transitions of 87Rb. We observe quadrature-dependent noise in the light signal, an indication that it may be possible to produce squeezed states of light. We measure the minimum and maximum phase-dependent noise as a function of detuning and compare these results to theoretical predictions to explore the best conditions for light squeezing using cold atomic Rb.

Optical Manipulation of Light Scattering in Cold Atomic Rubidium

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.

Light scattering on the F = 1 → F′ = 0 transition in a cold and high density 87Rb vapor

We report an experimental study of near resonance light scattering on the component of the line in atomic . Experiments are performed on spatially bi-Gaussian ultracold gas samples having peak densities ranging from about – atoms/cm and for a range of resonance saturation parameters and detunings from atomic resonance. Time resolution of the scattered light intensity reveals the dynamics of light scattering, optical pumping, and saturation effects. The experimental line shape for optical excitation in steady state is found to be significantly narrower than that for the transition studied previously under similar conditions. This difference is qualitatively reproduced by a theoretical model of the two transitions at similar density.

Spectral dependence of diffuse light dynamics in ultracold atomic 85 Rb

We report a combined experimental and theoretical simulation of multiply scattered light dynamics in an ultracold gas of 85Rb atoms. Measurements of the spectral dependence of the time-decay of the scattered light intensity, following pulsed excitation with near resonance radiation, reveals that the decay for long times is nearly exponential, with a decay constant that is largely independent of detuning from resonance. Monte Carlo simulations of the multiple scattering process show that, for large detunings, near resonance scattering of Fourier components of the excitation pulse plays a significant role in the effect. This interpretation is supported by the observations, and successful modelling, of beating between Rayleigh scattered light at the excitation carrier frequency with the Fourier components of the excitation pulse that overlap significantly with the atomic resonance.

Alignment Dynamics of Slow Light Diffusion in Ultracold Atomic 85Rb

We report experimental and theoretical study of time- and polarization-dependent propagation of light in ultracold atomic Rb. Strong variations of the time-dependent electronic alignment in the vicinity of atomic resonance is measured.

Interference and dephasing in weak localization of light

We report effects influencing enhancement (E) in coherent backscattering (CBS) of resonance radiation from ultracold Rb, and may have strong influence on efforts to observe strong localization. Theoretical results predict destructive interference in CBS, E<1. Time-dependent measurements of E show the influence of time-separation of different light scattering orders.