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Kristiaan Neyts

Bio: Kristiaan Neyts is an academic researcher from Ghent University. The author has contributed to research in topics: Liquid crystal & Electroluminescence. The author has an hindex of 35, co-authored 367 publications receiving 4863 citations. Previous affiliations of Kristiaan Neyts include National Fund for Scientific Research & University of California, Berkeley.


Papers
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Kristiaan Neyts1
TL;DR: In this paper, a theoretical expression for the radiation pattern of light-emitting devices based on thin-film technology is provided, discriminating for polarization, emission angle, absorption, and transmission; and numerical calculation of discrete modes, narrow modes, and evanescent waves near absorbing media is discussed.
Abstract: In light-emitting devices based on thin-film technology, light waves that are partially or totally reflected at interfaces between different materials interfere and influence the angular distribution of the emitted light. For an electrical dipole transition, the radiation pattern is equivalent to that of an electrical dipole antenna. New theoretical expressions are provided for the radiation, discriminating for polarization, emission angle, absorption, and transmission; and the numerical calculation of discrete modes, narrow modes, and evanescent waves near absorbing media is discussed.

299 citations

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TL;DR: In this article, the use of liquid crystals in different photonic components: optical filters and switches, beam-steering devices, spatial light modulators, integrated devices based on optical waveguiding, lasers, and optical nonlinear components are discussed.
Abstract: Liquid crystals are nowadays widely used in all types of display applications. However their unique electro-optic properties also make them a suitable material for nondisplay applications. We will focus on the use of liquid crystals in different photonic components: optical filters and switches, beam-steering devices, spatial light modulators, integrated devices based on optical waveguiding, lasers, and optical nonlinear components. Both the basic operating principles as well as the recent state-of-the art are discussed.

215 citations

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TL;DR: In this paper, the effect of a dielectric capping layer on the outcoupled light intensity in forward direction was investigated in top-emitting organic light emitting devices (OLEDs).
Abstract: The emission characteristics of top-emitting organic light-emitting devices (OLEDs) have been studied experimentally and theoretically to derive a quantitative understanding of the effect of a dielectric capping layer We demonstrated that the angular intensity distribution and the spectral characteristics can be tuned and the light outcoupling enhanced simply by varying the optical thickness of a dielectric layer deposited on top of a semitransparent metal electrode With the capping-layer concept, the outcoupled light intensity in forward direction was increased by a factor of 17, and concomitantly a high color purity achieved An optical model based on a classical approach was used to calculate the emission characteristics The excellent agreement between measured and simulated data shows that the capping layer controls the interplay between different interference effects such as wide-angle and multiple-beam interference occurring in top-emitting OLEDs The strength of the capping layer concept is in

196 citations

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TL;DR: In this paper, the first electro-optic modulators based on ferroelectric lead zirconate titanate (PZT) films on SiN, in both the O- and the C-band, were demonstrated.
Abstract: Silicon nitride (SiN) is emerging as a competitive platform for CMOS-compatible integrated photonics. However, active devices such as modulators are scarce and still lack in performance. Ideally, such a modulator should have a high bandwidth, good modulation efficiency, low loss, and cover a wide wavelength range. Here, we demonstrate the first electro-optic modulators based on ferroelectric lead zirconate titanate (PZT) films on SiN, in both the O- and the C-band. Bias-free operation, bandwidths beyond 33 GHz and data rates of 40 Gbps are shown, as well as low propagation losses ($\alpha\approx 1$ dB/cm). A $V_\pi L\approx$ 3.2 Vcm is measured. Simulations indicate that values below 2 Vcm are achievable. This approach offers a much-anticipated route towards high-performance phase modulators on SiN.

134 citations

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TL;DR: The authors demonstrate the first electro-optic modulators based on ferroelectric lead zirconate titanate films on silicon nitride, in both the O- and the C-band with a modulation bandwidth beyond 33 GHz and with data rates of 40 Gbps.
Abstract: Silicon nitride (SiN) is emerging as a competitive platform for CMOS-compatible integrated photonics. However, active devices such as modulators are scarce and still lack in performance. Ideally, such a modulator should have a high bandwidth, good modulation efficiency, low loss, and cover a wide wavelength range. Here, we demonstrate the first electro-optic modulators based on ferroelectric lead zirconate titanate (PZT) films on SiN, in both the O-band and C-band. Bias-free operation, bandwidths beyond 33 GHz and data rates of 40 Gbps are shown, as well as low propagation losses (α ≈ 1 dB cm−1). A half-wave voltage-length product of 3.2 V cm is measured. Simulations indicate that further improvement is possible. This approach offers a much-anticipated route towards high-performance phase modulators on SiN. Active devices such as modulators made of silicon nitride still lack performance. Here, the authors demonstrate electro-optic modulators based on ferroelectric lead zirconate titanate films on silicon nitride, in both the O- and the C-band with a modulation bandwidth beyond 33 GHz and with data rates of 40 Gbps.

132 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

Journal ArticleDOI
TL;DR: This critical review describes the latest developments in the sensitization of near-infrared luminescence, "soft" luminescent materials (liquid crystals, ionic liquids, ionogels), electroluminescentmaterials for organic light emitting diodes, with emphasis on white light generation, and applications in luminecent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation.
Abstract: Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

2,895 citations

01 May 2005

2,648 citations

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TL;DR: The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Abstract: The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

2,582 citations