144 research outputs found

    EFFECTIVE WEB DEVELOPMENT

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    THE METHODOLOGICAL PRINCIPLES OF GENOCIDE TEACHING IN THE SCHOOL COURSE OF HISTORY

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    Teaching history of genocides has taken a special place in the school history course. This article describes basic methodological principles of teaching the genocides topic in the school history course. There are defined teacher’s methodical mistakes in the process of teaching the history of genocides. The article is focused in the importance of using cross-curricular themes and different aspects in teaching the history of genocides. There is a based conclusion about the necessity of the organization of teaching the history of genocides from the point of the social psychology. There is a question defined on the comparative teaching of history of genocides.KEY WORDS: genocide, education, teaching of history, Holocaust.JEL CODES: I20, I21, I29DOI: http://dx.doi.org/10.15181/rfds.v18i1.124

    Ultrabroadband Nonlinear Optics in Nanophotonic Periodically Poled Lithium Niobate Waveguides

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    Quasi-phasematched interactions in waveguides with quadratic nonlinearities enable highly efficient nonlinear frequency conversion. In this article, we demonstrate the first generation of devices that combine the dispersion-engineering available in nanophotonic waveguides with quasi-phasematched nonlinear interactions available in periodically poled lithium niobate (PPLN). This combination enables quasi-static interactions of femtosecond pulses, reducing the pulse energy requirements by several orders of magnitude, from picojoules to femtojoules. We experimentally demonstrate two effects associated with second harmonic generation. First, we observe efficient quasi-phasematched second harmonic generation with <100 fJ of pulse energy. Second, in the limit of strong phase-mismatch, we observe spectral broadening of both harmonics with as little as 2-pJ of pulse energy. These results lay a foundation for a new class of nonlinear devices, in which co-engineering of dispersion with quasi-phasematching enables efficient nonlinear optics at the femtojoule level

    Ultra-low loss integrated visible photonics using thin-film lithium niobate

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    Integrated photonics is a powerful platform that can improve the performance and stability of optical systems, while providing low-cost, small-footprint and scalable alternatives to implementations based on free-space optics. While great progress has been made on the development of low-loss integrated photonics platforms at telecom wavelengths, visible wavelength range has received less attention. Yet, many applications utilize visible or near-visible light, including those in optical imaging, optogenetics, and quantum science and technology. Here we demonstrate an ultra-low loss integrated visible photonics platform based on thin film lithium niobate on insulator. Our waveguides feature ultra-low propagation loss of 6 dB/m, while our microring resonators have an intrinsic quality factor of 11 million, both measured at 637 nm wavelength. Additionally, we demonstrate an on-chip visible intensity modulator with an electro-optic bandwidth of 10 GHz, limited by the detector used. The ultra-low loss devices demonstrated in this work, together with the strong second- and third-order nonlinearities in lithium niobate, open up new opportunities for creating novel passive, and active devices for frequency metrology and quantum information processing in the visible spectrum range
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