Search results for "Nonlinear optic"

Nonlinear optical susceptibilities of polysilanes: exciton effect

1992

Abstract Third-order nonlinear optical susceptibilities of σ-conjugated one-dimensional polymers have been calculated in a tight-binding model by taking account of the formation of excitons due to long-range Coulomb interactions. The spectrum of third-harmonic generation (THG) exhibits peaks due to excitons as well as unbound electron—hole states, in contrast to the linear absorption spectrum which is dominated by the lowest exciton state. The results are in excellent agreement with recent experiments in polysilanes not only for THG but also for linear absorption, two-photon absorption, and electroabsorption in a mutually consistent way.

Hybrid silicon on insulator/polymer electro-optical intensity modulator operating at 780  nm

2014

Currently inorganic materials prevail as the nonlinear active medium for light modulation in electro-optical (EO) device technology. A recent promising trend is to consider organic nonlinear optical materials for application in EO modulators due to their multiple advantages including low costs and high EO coefficients. In this paper, we proposed a new type of polymer EO modulator whose fabrication is compatible with the currently used silicon on insulator technology. Our numerical optimization of the proposed structure demonstrates that it is theoretically possible to achieve a half-wave voltage as low as 1.56 V for a 1 cm long modulator structure operating at 780 nm. Based on the results o…

NLO-polymers containingtert-butyloxycarbonyl protecting groups: Modification after processing leading to thermally stable nonlinear optical materials

1997

Mixed polymeric monolayers and Langmuir-Blodgett multilayers with functional low molecular weight guest compounds

2008

Abstract Mixed monolayers and Langmuir-Blodgett multilayers of functional low molecular weight guest compounds, especially nonlinear optical (NLO) dyes, within the matrix of an amphotropic spacer polymer have been prepared. The polymer matrix enabled the transfer of guest compounds not capable of self-organizing at the air-water interface by themselves. The structure of the LB multilayers and the transfer process were studied by small angle X-ray scattering and UV-visible spectroscopy. Good NLO coefficients were found in the mixed films.

Solvatochromy and electro-optical study of new fluorine-containing chromophores

1998

technology requires tailored functional materials which fulfill the demands for optimal operation parameters, reliability andprocessability. Organic chromophores and polymers which contain covalently bound chromophores are promising materialclasses which can satisfy a broad spectrum of demands on functional materials for photonics, and they are, therefore,favorites for the development of new photonic devices. However, it is almost impossible to satisfy all physico-chemical andtechnological requirements simultaneously with a polymer consisting of only one type of functional unit. The developmentof a series of different building blocks which allow to cover the whole range of physico-chemical …

Spectroscopic Investigations Of LB Mono- And Multilayers Of 2-docosylamino 5-nitropyridine; Promising Candidates For Non-linear And Integrated Optics

2005

Alkylamino-5-nitropyridineshavemently been introduced forthepreparation of a novel type of non-centrosymmetric Langmuir-Blodgett (LB) multilayer (1,2). Hitherto, second order non-linear optical investigations have been resmcted toLB-films oftwomaterialsinaltematinglayerstructureand to films of a single material with head to tail arrangement of the molecules, both of whicharedifficulttoobtain (seerefs. quotedin 1 and2.1. Incontrast,allpresent data indicate that LB-filmsof 2-aUcylamino-5-nitropyridines are head-to-head and tail-to-tail (Y-type) multilayers with a rather strong tilt-angle of the alkyl chains (Fig. I). The most effective substance for second order non-linear optical experiments…

Poling dynamics of an EO active material using parallel-plate electrodes

2017

We describe the sample preparation and experimental setup for second harmonic generation measurement of electro-optical (EO) chromophore/polymer system at the time of contact-poling. Different types of spacers for avoiding electric breakdown due to avalanche multiplication are compared. Electric field threshold values for second harmonic generation are observed in all samples.

Design and Optimization of Chromophores for Liquid Crystal and Photorefractive Applications

1999

ABSTRACTOrganic chromophores have been exploited for a wide range of discrete optical and electronic functions as well as a growing number of combined opto-electronic functions. We are pursuing development of organic and polymer materials for a range of applications that require properties including liquid crystallinity, second order optical nonlinearity, photorefractivity and, more recently, special nonlinear optical behavior involving molecular chirality.

Halogen bonding enhances nonlinear optical response in poled supramolecular polymers

2015

We demonstrate that halogen bonding strongly enhances the nonlinear optical response of poled supramolecular polymer systems. We compare three nonlinear optical chromophores with similar electronic structures but different bond-donating units, and show that both the type and the strength of the noncovalent interaction between the chromophores and the polymer matrix play their own distinctive roles in the optical nonlinearity of the systems. acceptedVersion Peer reviewed

Electron crystallography and organic materials with non-linear optical properties

1999

Results of electron microscopic studies of crystal structures of a number of bis-benzylidene cyclohexanones are presented. It is shown that some of these compounds are efficient crystalline non-linear optically active (NLO) chromophores with second harmonic generation (SHG) properties. Appropriately functionalized chromophores of this type can be used as a polycondensation comonomer to produce partly crystalline main-chain NLO-active polymers. Electron diffraction crystal structural data, obtained for very small crystals, allowed us to get reasonable estimations of macroscopic crystal NLO-coefficients, relating quantum-chemically calculated molecular first hyperpolarizability components to …