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The results of an experimental study of population dynamics following excitation of 62D5/2, 3/2 and 82S1/2 states of rubidium are reported. Excitation transfer and quenching cross-sections in collisions with ground state rubidium atoms, and natural lifetimes have been measured. The experiment was performed in a vapour cell, using pulsed two-photon excitation and photon counting detection. The analysis of time dependent signals was based on a rate equation model in which transitions induced by thermal radiation have been accounted for. The measurements yielded following results: (1) 62D state J-mixing cross-section: σ = 9.2(2.1) × 10−14 cm2; (2) cross-sections for 82S → 62D excitation transfer process: σ = 3.4(1.2) × 10−14 cm2; (3) quenching cross-sections: σ = 12,8(3.4) × 10−14 cm2, σ = 22.8(2.9) × 10−14 cm2, σ = 14.1(5.7) × 10−14 cm2; (4) radiative lifetimes: τ 8S = 161(3) ns, τ 6D 3/2 = 256(4) ns, τ 6D 5/2 = 249(5) ns. [ABSTRACT FROM AUTHOR]

The results of an experimental study of population dynamics following excitation of [0pt] and [0pt] states of rubidium are reported. Excitation transfer and quenching cross-sections in collisions with ground state rubidium atoms, and natural lifetimes have been measured. The experiment was performed in a vapour cell, using pulsed two-photon excitation and photon counting detection. The analysis of time dependent signals was based on a rate equation model in which transitions induced by thermal radiation have been accounted for. The measurements yielded following results: (1) [0pt] state J-mixing cross-section: [0pt] ; (2) cross-sections for [0pt] excitation transfer process: [0pt] ; (3) quenching cross-sections: [0pt] , [0pt] , [0pt] ; [0pt](4) radiative lifetimes: [0pt] ns, [0pt] ns, [0pt] ns. [ABSTRACT FROM AUTHOR]

We report measurements of lifetimes of the Rb( n F)( n=6, 7, 8) states performed in a vapour cell. The F-states were excited in a two-step sequence of an electric-dipole transition followed by an electric-quadrupole transition. Single photon counting was used for detection. The results are: τ(6 F)=171(4), τ(7 F)=262(15), τ(8 F)=387(12) (in ns). These lifetimes, have been compared with theoretical values given by different authors. An estimate of the cross sections for quenching due to collisions with ground-state Rb atoms is also given. [ABSTRACT FROM AUTHOR]

We calculate electric susceptibility of a laser-dressed atomic medium. The model adopted in this work refers to the experiment with cold 85Rb atoms, where the states F' = 1, 2, 3 of the hyperfine manifold 5P3/2 (F') are strongly coupled with the ground state 5S1/2 (F = 2), and the coupling is probed by a weak probing field from the other ground-state component 5S1/2 (F = 3). We present a five-level model in which the states F = 2, 3 and F' = 1, 2, 3 are taken into account, while the noncoupled state F' = 4 is neglected. The model is used as a starting point to reproduce spectral features observed in the absorption of probe light passing through a cold sample of 85Rb atoms in a magneto-optical trap. Basing on numerical solutions of this model, we have also studied in detail the impact on the probe spectra from the presence of the state F' = 1 to which probing is forbidden by electric-dipole transition, but coupling is allowed [see, e.g., Proc. of SPIE 8770 (2013) 87700Q]. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this work was to provide a simple justification and applicability limits for the concept of effective Rabi frequency being related to an average atom–field interaction in MOT. We sampled 85Rb MOT with a weak probe beam tuned across the 5P3/2 (F′ =4)→5D5/2(F″= 3, 4, 5) hyperfine transitions, while the 5S1/2(F =3) → 5P3/2(F′ =4) transition was driven by the red-detuned trapping beam. The probe absorption spectra were registered for a number of detunings Δ and intensities P of the trapping beam. The Autler–Townes splitting δ of the clearly dominating F′ =4→ F″ =5 line was the subject of analysis. The character of the space-dependent interactions of atoms with MOT fields is of a complex nature, which brings the notion of the effective Rabi frequency for MOT into challenge. However, we argue that for the range of the typical values of P and Δ, it is justified to characterize MOT with an effective Rabi frequency Ω 0eff, by using the intuitive formula , where is a mean scaling factor experimentally determined, basing on predictions of a straightforward 3-level model. We postulate that our simple procedure, providing both the value and the applicability limits of the approach, should be repeated with each new implementation of MOT (e.g., with trap beams realignment), which may change conditions experienced by cold atoms. [Copyright &y& Elsevier]

Abstract: We have investigated multiple windows of electromagnetically induced transparency (EIT) registered in a cascade scheme 5S1/2(F=3)→5P3/2(F′=3)↔5D5/2(F″=4, 3, 2) of cold 85Rb atoms in a magneto-optical trap (MOT), with a weak probe laser in the first step and with a strong coupling laser in the second step. A structure composed of up to three transparency windows is observed in the spectral profile of the probe absorption, due to a simultaneous coupling of three F″ components of a dense hfs structure of a 5D5/2 state of the 85Rb isotope. The experimental EIT features, as dependent on the coupling beam intensity or on the frequency detuning from the F′=3↔F″=3 resonance are compared with those theoretically obtained from a five-level model. A coefficient characterizing a relative decrease of absorption at the center of the most prominent EIT peak, plotted versus the coupling beam intensity, is also presented for both the experimental and modeled spectra. A good agreement between theory and experiment is observed. As it is very simple to manipulate the positions, shapes and depths of the EIT features, the present scheme could be of interest, e.g., for the quantum information science. [Copyright &y& Elsevier]

The possible use of the nonlinear Faraday effect for optical limitation of the laser power is investigated in a resonant Faraday medium placed between two crossed polarizers. The results are comparable with those obtained at strong magnetic fields as a result of the linear Faraday effect. Advantages of the method are the narrow bandwidth and the wide field of view. The investigations are interesting from the viewpoint of applications for optical sensor protection and automation of the experiment. All measurements are performed at the F(g) = 2 --> F(e) = 1 hyperfine structure transition of the 87Rb D1 line.

The aim of this study was to estimate the coexistence of risk factors for coronary heart disease (CHD) in hyperlipidemic patients. Studies were performed in 1002 (601 women, 401 men) subjects who referred to our outpatient clinic among 12 months. Hypercholesterolemia was the predominant lipid disorder found in 66% of patients, mixed hyperlipidemia in 31.8%, and hypertriglyceridemia only in 2.2%. Overweight and obesity remain a major health burden among our patients: BMI > or = 25 was observed in 66%. Hypertension was recognized in 37.5% of subjects, and diabetes mellitus in 11.2%, 17% were long-term smokers. Familial aggregation of hyperlipidemia was observed in 15.7% of subjects, and more than 44% had a positive family history of cardiovascular disease. Low HDL cholesterol levels (< 35 mg/dl) were seen frequently in men (24.7%) and rare in women (7%). Lp(a) excess (> or = 30 mg/dl) was observed in 12% of patients. Myocardial infarction (MI) had already 11.7% subjects (7% women, 18.7% men). In these patients CHD risk factors were observed more frequently. The higher apo B and Lp(a) levels and lower HDL cholesterol levels were recognized in the patients who suffered from MI. More than 83% of our hyperlipidemic patients had coexistence CHD risk factors. The multiple coexisting risk factors cause the high risk for CHD and they require intensive correction.