41 research outputs found

    Optical pulse propagation in a switched-on photonic lattice: Rabi effect with the roles of light and matter interchanged

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    A light pulse propagating in a suddenly switched on photonic lattice, when the central frequency lies in the photonic band gap, is an analog of the Rabi model where the two-level system is the two resonant (i.e. Bragg-coupled) Fourier modes of the pulse, while the photonic lattice serves as a monochromatic external field. A simple theory of these Rabi oscillations is given and confirmed by the numerical solution of the corresponding Maxwell equations. This is a direct, i.e. temporal, analog of the Rabi effect, additionally to the spatial analog in optical beam propagation described in Opt. Lett. 32, 1920 (2007). An additional high-frequency modulation of the Rabi oscillations reflects the lattice-induced energy transfer between the electric and magnetic fields of the pulse.Comment: 3 pages, 5 figure

    Resonance Absorption of Light By Subwavelength Diffractive Gratings

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    Diffraction of light of a visible spectral range by subwavelength metal gratings is investigated theoretically and experimentally. The influence of different grating parameters (filling factor, shape and depth, material, angle of incidence, wavelength and polarization of radiation) on diffraction efficiency is investigated. The conditions are found under which there are only zero diffraction order and the minus first order. It is established that the zero order can be suppressed by selecting the depth and shape of the grating relief. High diffraction efficiency in the -1st order is observed with increasing depth of the grating relief (more than 70% at a depth h = 80 nm). It is shown that under certain conditions an effect of plasmon resonance occurs, at which there is a complete absorption of the incident radiation. The considered optical elements can be used in systems for image processing, projection displays, in the development of a variety of sensors, etc. Keywords: subwavelength grating, diffraction efficiency, plasmon resonanc

    Superefficient one-dimensional mode-solver

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    Neurocognition in schizophrenia: a study of the productivity and visibility of spanish authors

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    This paper provides a map of the scientific productivity of authors affiliated to a Spanish institution and who have addressed one of the most important current topics in schizophrenia: The study of cognitive performance. A search of the Web of Science yielded 125 articles that met the inclusion criteria. In order to provide a comprehensive overview of scientific productivity, we examine several bibliometric indicators, concerning both productivity and impact or visibility. The analysis also focuses on qualitative aspects of key theoretical importance, such as the kinds of cognitive functions that are most often assessed and the tests most widely used to evaluate them in clinical practice. The study shows that interest in the subject of cognitive function in schizophrenia has increased considerably in Spain since the beginning of this century. The results also highlight the need to standardize the type of tests to be used in the cognitive assessment of patients with schizophrenia

    The mechanism of cortical control over the thyroid

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