Electromagnetically induced transparency in inhomogeneously broadened Lambda-transition with multiple excited levels

Electromagnetically induced transparency (EIT) has mainly been modelled for three-level systems. In particular, a considerable interest has been dedicated to the Lambda-configuration, with two ground states and one excited state. However, in the alkali-metal atoms, which are commonly used, hyperfine interaction in the excited state introduces several levels which simultaneously participate in the scattering process. When the Doppler broadening is comparable with the hyperfine splitting in the upper state, the three-level Lambda model does not reproduce the experimental results. Here we theoretically investigate the EIT in a hot vapor of alkali-metal atoms and demonstrate that it can be strongly reduced due to the presence of multiple excited levels. Given this model, we also show that a well-designed optical pumping enables to significantly recover the transparency

High frequency polarization switching of a thin ferroelectric film

We consider both experimentally and analytically the transient oscillatory process that arises when a rapid change in voltage is applied to a $Ba_xSr_{1-x}TiO_3$ ferroelectric thin film deposited on an $Mg0$ substrate. High frequency ($\approx 10^{8} rad/s$) polarization oscillations are observed in the ferroelectric sample. These can be understood using a simple field-polarization model. In particular we obtain analytic expressions for the oscillation frequency and the decay time of the polarization fluctuation in terms of the material parameters. These estimations agree well with the experimental results

Quantum memory for light via stimulated off-resonant Raman process: beyond the three-level Lambda-scheme approximation

We consider a quantum memory scheme based on the conversion of a signal pulse into a long-lived spin coherence via stimulated off-resonant Raman process. For a storing medium consisting of alkali atoms, we have calculated the Autler-Townes resonance structure created by a strong control field. By taking into account the upper hyperfine states of the D1 optical transition, we show important deviations from the predictions of the usual three-level Lambda-scheme approximation and we demonstrate an enhancement of the process for particular detunings of the control. We estimate the memory efficiency one can obtain using this configuration.Comment: 8 pages, 6 figure

Ferroelectric Nanotubes

We report the independent invention of ferroelectric nanotubes from groups in several countries. Devices have been made with three different materials: lead zirconate-titanate PbZr1-xTixO3 (PZT); barium titanate BaTiO3; and strontium bismuth tantalate SrBi2Ta2O9 (SBT). Several different deposition techniques have been used successfully, including misted CSD (chemical solution deposition) and pore wetting. Ferroelectric hysteresis and high optical nonlinearity have been demonstrated. The structures are analyzed via SEM, TEM, XRD, AFM (piezo-mode), and SHG. Applications to trenching in Si dynamic random access memories, ink-jet printers, and photonic devices are discussed. Ferroelectric filled pores as small as 20 nm in diameter have been studied

О ВОЗМОЖНОСТИ МЕЖДИСЦИПЛИНАРНОЙ ИНТЕГРАЦИИ РУССКОГО ЯЗЫКА И ХИМИИ В СТАРШИХ КЛАССАХ ОБЩЕОБРАЗОВАТЕЛЬНОЙ ШКОЛЫ

A study in the field of interdisciplinary interference of the Russian language and chemistry in high school.Проведено исследование в области междисциплинарной интеграции русского языка и химии в старших классах общеобразовательной школы

АНАЛИЗ И ДИАГНОСТИКА УРОВНЕЙ УЧЕБНО-ИНФОРМАЦИОННЫХ УМЕНИЙ СТУДЕНТОВ 1-ОГО КУРСА ЕСТЕСТВЕННО-НАУЧНОГО ФАКУЛЬТЕТА 2018–2019 ГОДА

This article diagnoses and analyzes the educational and information skills of first-year students. В данной статье диагностируются и анализируются учебно-информационные умения студентов первого курса.

Photoinduced dynamics in ferroelectric semiconductor Sn2P2S6

This work was partly supported by the Russian Ministry of Science and Higher Education (grant 3.7500.2017/9.10) and Russian Foundation of Basic Research (grant 18-32-20047). The studies were performed using the equipment of the Joint Center for Collective Use RTU MIREA