1,016 research outputs found
Observation of polarization quantum noise of laser radiation in Rb vapor cell
We present experimental study of polarization quantum noise of laser
radiation passed through optically think vapor of Rb87. We observe a step-like
noise spectrum. We discuss various factor which may result in such noise
spectrum and prevent observation of squeezing of quantum fluctuations predicted
in Matsko et al. PRA 63, 043814 (2001).Comment: 4 pages, 5 figures. Translated from Russian by I. Novikov
Enhancement of Kerr nonlinearity via multi-photon coherence
We propose a new method of resonant enhancement of optical Kerr nonlinearity
using multi-level atomic coherence. The enhancement is accompanied by
suppression of the other linear and nonlinear susceptibility terms of the
medium. We show that the effect results in a modification of the nonlinear
Faraday rotation of light propagating in an Rb87 vapor cell by changing the
ellipticity of the light.Comment: 4 pages, 3 figures Submitted to Optics Letter
Temperature dependence of the electron spin g factor in GaAs
The temperature dependence of the electron spin factor in GaAs is
investigated experimentally and theoretically. Experimentally, the factor
was measured using time-resolved Faraday rotation due to Larmor precession of
electron spins in the temperature range between 4.5 K and 190 K. The experiment
shows an almost linear increase of the value with the temperature. This
result is in good agreement with other measurements based on photoluminescence
quantum beats and time-resolved Kerr rotation up to room temperature. The
experimental data are described theoretically taking into account a diminishing
fundamental energy gap in GaAs due to lattice thermal dilatation and
nonparabolicity of the conduction band calculated using a five-level kp model.
At higher temperatures electrons populate higher Landau levels and the average
factor is obtained from a summation over many levels. A very good
description of the experimental data is obtained indicating that the observed
increase of the spin factor with the temperature is predominantly due to
band's nonparabolicity.Comment: 6 pages 4 figure
Communicative search for a way out of the impasse in cross-cultural communication: conditions for narrowing the "gaps" between the languages
The paper addresses the issue of linguistic differences in cross-cultural communication and discusses communicative strategies that could be used to mitigate them. The authors argue that lingua-didactic multicultural education can help remove the main obstacle in the traditional teaching of Russian as a foreign language (RFL) - a "clash of cultures"; and not only can introduce a model of teaching to write, read, and speak in Russian, but can also offer a system of instruction that will allow the students to understand the way Russians think, which surely would make it easier for them to "translate" a text from one culture into another in a non-native "cultural environment" providing a polylingual format for interactio
Comparison of 87Rb N-resonances for D1 and D2 transitions
We report an experimental comparison of three-photon-absorption resonances
(known as "N-resonances") for the D_1 and D_2 optical transitions of thermal
87Rb vapor. We find that the D_2 N-resonance has better contrast, a broader
linewidth, and a more symmetric lineshape than the D_1 N-resonance. Taken
together, these factors imply superior performance for frequency standards
operating on alkali D_2 N-resonances, in contrast to coherent population
trapping (CPT) resonances for which the D_2 transition provides poorer
frequency standard performance than the D_1 transition.Comment: 3 pages, 4 figure
Scenarios of increasing the economic efficiency of the Kaliningrad regional transport system
The development of the considerable transport and logistics potential of the Kaliningrad region is hampered by several factors. This problem, to which we will refer to as a transport deadlock effect, translates into the limited contribution of transport to the regional economy. Particularly, it manifests itself at the level of regional gross value added, where the contribution of transport is much smaller than one might expect given the significant role the industry plays in the economy of the region. In this study, we examine major ways of increasing the economic efficiency of the regional transport system from the value added perspective. We posit that the structure of cargo handled and the redistribution of value added in favour of regional actors have the dominant influence on economic efficiency. Using our own simulation model and the earlier developed system of transport tariffs and value added calculation for the Kaliningrad region, we produce scenarios and consider changes in value added in the case of selected cargoes carrying intermediate, investment, and consumer goods (as defined in the International Classification for Broad Economic Categories ICT BEC-4). Our calculations show that higher value added and greater economic efficiency of a regional transport system are associated with re-orientation towards investment and consumer goods. The most visible effect is associated with rail and road transport. As to sea transport, the decisive role is played by an increase in the physical volume of cargo handled. The results of this study and its modelling tools can be applied in the analysis of the current situation and in the assessment of the efficiency of transport systems in other regions. Another possible application is the identification of growth conditions for an industry, particularly, when developing projects and proposals for increasing the efficiency of transport services
Nonlinear Magneto-Optical Rotation of Elliptically Polarized Light
We predict theoretically and demonstrate experimentally an ellipticity-dependent nonlinear magneto-optic rotation of elliptically-polarized light propagating in a coherent atomic medium. We show that this effect results from a hexadecapole and higher order momenta of atomic coherence, and is associated with an enhancement of Kerr and higher orders nonlinearities accompanied by suppression of the other linear and nonlinear susceptibility terms of the medium. These nonlinearities might be useful for quantum signal processing. In particular, we report an observation of an enhancement the polarization rotation of elliptically polarized light resonant with the 5S_{1/2} F=2 -> 5P_{1/2} F=1 transition of Rb87
A novel absorption resonance for all-optical atomic clocks
We report an experimental study of an all-optical three-photon-absorption
resonance (known as a "N-resonance") and discuss its potential application as
an alternative to atomic clocks based on coherent population trapping (CPT). We
present measurements of the N-resonance contrast, width and light-shift for the
D1 line of 87Rb with varying buffer gases, and find good agreement with an
analytical model of this novel resonance. The results suggest that N-resonances
are promising for atomic clock applications.Comment: 4 pages, 6 figure
Gaming as Means of Teaching Foreign Language Communication
The problem of using foreign language as means of communication between professionals with different cultural backgrounds is considered. Attention is paid to the communicationoriented and professionally-directed nature of the course of learning a foreign language in not-linguistic high school. The defining characteristics of the learning process organized with gaming using are described. General overview of the typology of pedagogical games is made.Рассматривается проблема использования иностранного языка как средства общения между специалистами, представляющими разные культуры. Уделяется внимание коммуникативно-ориентированному и профессионально-направленному характеру курса обучения иностранному языку в неязыковом вузе. Описываются определяющие характеристики процесса обучения, организованного с использованием гейминга. Выполнен общий обзор типологии педагогических игр
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