1,615 research outputs found

    Silicon-organic hybrid electro-optical devices

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    Organic materials combined with strongly guiding silicon waveguides open the route to highly efficient electro-optical devices. Modulators based on the so-called silicon-organic hybrid (SOH) platform have only recently shown frequency responses up to 100 GHz, high-speed operation beyond 112 Gbit/s with fJ/bit power consumption. In this paper, we review the SOH platform and discuss important devices such as Mach-Zehnder and IQ-modulators based on the linear electro-optic effect. We further show liquid-crystal phase-shifters with a voltage-length product as low as V pi L = 0.06 V.mm and sub-mu W power consumption as required for slow optical switching or tuning optical filters and devices

    A stable liquid crystal for electro-optical displays

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    Method is reported for substitution of hydroxy (OH) group ortho to anil linkage to stabilize anil-type liquid crystal for use in electro-optical devices

    Co-integration of Ge detectors and Si modulators in an advanced Si photonics platform

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    A Si photonics platform is described, co-integrating advanced passive components with Si modulators and Ge detectors. This platform is developed on a 200mm CMOS toolset, compatible with a 130nm CMOS baseline. The paper describes the process flow, and describes the performance of selected electro-optical devices to demonstrate the viability of the flow

    Chiroptical Spectroscopy of C3 Molecules

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    The relevance of molecules with C3 symmetry comes from the fact of many of them, upon assembling as columnar helical macromolecules, are ideal platform for electro-optical devices, for example as liquid crystals. The properties of these devices are highly dependent of the structure of the bulk aggregates, and consequently they can be controlled by modifying the position and nature of the stereocenters in the molecular building blocks. In this work we present an electronic and vibrational chiroptical study on a series of star-shaped molecules based on the octopolar C3-symmetric 1,3,5-(phenylene-ethynylene)-benzene block.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

    Exciton Ionization, Franz-Keldysh and Stark Effects in Carbon Nanotubes

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    We calculate the optical properties of carbon nanotubes in an external static electric field directed along the tube axis. We predict strong Franz-Keldysh oscillations in the first and second band-to-band absorption peaks, quadratic Stark effect of the first two excitons, and the field dependence of the bound exciton ionization rate for a wide range of tube chiralities. We find that the phonon assisted mechanism dominates the dissociation rate in electro-optical devices due to the hot optical phonons. We predict a quadratic dependence of the Sommerfeld factor on the electric field and its increase up to 2000% at the critical field of the full exciton dissociation.Comment: 12 pages, 5 figures, Nano Letters (2007

    Efficient generation and control of different order orbital angular momentum states for communication links

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    We present a novel optical device to encode and decode two bits of information into different Orbital Angular Momentum (OAM) states of a paraxial optical beam. Our device generates the four angular momentum states of order ±2\pm 2 and ±4\pm4 by Spin-To-Orbital angular momentum Conversion (STOC) in a triangular optical loop arrangement. The switching among the four OAM states is obtained by changing the polarization state of the circulating beam by two quarter wave plates and the two-bit information is transferred to the beam OAM exploiting a single qq-plate. The polarization of the exit beam is left free for additional one bit of information. The transmission bandwidth of the device may be as large as several megahertz if electro-optical switches are used to change the beam polarization. This may be particularly useful in communication system based on light OAM.Comment: 5 pages, 5 figures, 1 table. Submitte

    Polymer dispersed liquid crystals and related electro-optical devices - An overview

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    Open Access in ZenodoTo have a polymer dispersed liquid crystal (PDLC), the liquid crystalline material is dispersed into a liquid polymer. When the polymer changes from liquid to solid, the liquid crystal becomes incompatible with the polymer and creates dispersed droplets throughout the polymeric film. The film can be processed by standard techniques to have large and environmentally robust displays and light shutters. This paper describes PDLC films and their properties in a simplified approach, suitable for teaching the devices based on such films to students of university courses
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