Nonlinear optical properties of organic and polymeric materials
29 Sep 1983-
About: The article was published on 1983-09-29 and is currently open access. It has received 762 citations till now.
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01 Jan 1987
TL;DR: In this paper, a nonlinear transport equation is presented based on a density matrix formalism and a non-linear Hamiltonian for charge transport in organic conductors, which can describe both local and displacive transitions and gives a physically intuitive picture of the concept of off-diagonal long-range order and Bose-Einstein condensation.
Abstract: The density matrix approach to the constitutive relation between electric fields and the current density in organic polymers is compatible with a nonlinear transport equation. The derivation of such an equation is fundamental to any understanding of conduction in submicron devices, in organic polymers and in multiple quantum well structures—which may be considered the ultimate submicron devices—and also to understanding the nonlinear optical properties of those same polymers and materials. As a theoretical platform for such a derivation, physical models are introduced based on the long Josephson junction and the nonlinear line of pendula. A nonlinear transport equation is presented based on a density matrix formalism and a nonlinear Hamiltonian for charge transport in organic conductors. The equation can describe both local and displacive transitions and gives a physically intuitive picture of the concept of off-diagonal long-range order and Bose-Einstein condensation.
2 citations
TL;DR: In this article, thin films of alkyl conjugated donor-acceptor (D-A) molecules were investigated by ultraviolet-visible-near infrared (UV-vis-NIR) spectroscopy, in-plane and out-of-plane X-ray diffraction (XRD), and second-harmonic generation (SHG) measurements.
Abstract: Thin films of alkyl conjugated donor–acceptor (D–A) molecules, prepared by a high-yielding addition reaction between electron-rich alkynes and tetracyanoethylene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ), were investigated by ultraviolet–visible–near infrared (UV–vis–NIR) spectroscopy, in-plane and out-of-plane X-ray diffraction (XRD), and second-harmonic generation (SHG) measurements. The variable self-assembling ability of D–A chromophores produced different molecular orientations in the thin films. The TCNQ-adducted D–A molecule formed a centrosymmetric bilayer structure based on the strong interactions between the chromophores, while the film of the TCNE-adducted counter molecule was composed of interdigitated alkyl layers and randomly oriented chromophores due to their weak interactions. The interfacial interactions between a substrate and a TCNE-adducted molecular layer were expected to induce a noncentrosymmetric chromophore orientation in the thin film, which produced an effective SHG coefficient (deff) of ca. 21 pm V-1 without electric poling.
2 citations
TL;DR: In this article, a poly α-methylstyrene polymer containing piperazyl nitrostilbene in the side chain was designed and synthesized in an attempt to enhance both the electro-optic coefficient, r33 and its temporal stability.
Abstract: Employing the conventional second-order nonlinear optical (NLO) chromophore such as nitrostilbene derivative, we synthesized a polymer composed of poly α-methylstyrene structure. New α-methylstyrene polymer containing piperazyl nitrostilbene in the side chain was designed and synthesized in an attempt to enhance both the electro-optic coefficient, r33 and its temporal stability. The polymer showed the high glass transition temperature (Tg) implying better temporal stability of the secondorder NLO property. This polymer film was corona-poled under 3.5–5 kV at the temperature which was either close to the Tg or higher than that. The electro-optic coefficient of this polymer was measured to be 23–28pm/V at 632.8 nm of He-Ne laser.
2 citations
01 Jan 1993
TL;DR: Although there has been a high level of interest in nonlinear optical effects for more than 20 years now, most of the work in this field has concentrated on the development of noncentrosymmetric inorganic compounds such as LiNbO3 and analogues of potassium dihydrogen phosphate (KDP) as mentioned in this paper.
Abstract: Although there has been a high level of interest in nonlinear optical effects for more than 20 years now, most of the work in this field has concentrated on the development of noncentrosymmetric inorganic compounds such as LiNbO3 and analogues of potassium dihydrogen phosphate (KDP). Many of these inorganic crystals have been commercialized in the form of single-crystal frequency convertors, electro-optic modulators, and more recently as simple waveguide couplers and switches. Since about 1975 there has been increasing interest in organic compounds with nonlinear optical properties as potential alternatives to the inorganics mentioned above (Williams, 1983, 1984; Chemla and Zyss, 1986). Much of the work has concentrated on second-order properties, although more recently third-order effects have also been described.
2 citations
TL;DR: In this article, nonlinear optical materials which are highly transparent and show large second harmonic generation coefficients were fabricated via the sol-gel process and incorporated into the silica network by polymerizing chromophore containing organo silanes such as N-[3-(Triethoxysilyl)propyl]-2, 4-dinitrophenylamine (TDP) and 3-(4-Formyl phenoxy)propylon trimethoxy silane (FPT).
Abstract: Nonlinear optical materials which are highly transparent and show large second harmonic generation coefficients were fabricated via the sol-gel process. Nonlinear chromophores were directly incorporated into the silica network by polymerizing chromophore containing organo silanes such as N-[3-(Triethoxysilyl)propyl]-2, 4-dinitrophenylamine (TDP) and 3-(4-Formyl phenoxy)propyl trimethoxy silane (FPT).
2 citations