Dispersion nonlinear optical properties

Simoni F 1997 Nonlinear Optical Properties of Liquid Crystals and Polymer-Dispersed Liquid Crystals (Singapore World Scientific)... 

Dispersion of Linear and Nonlinear Optical Properties of Benzene An Ab Initio Time-Dependent Coupled-Perturbed Hartree-Fock Study Shashi P. Kama, Gautam B. Talapatra and Paras N. Prasad Journal of Chemical Physics 95 (1991) 5873-5881... 

Bishop s attention turned to accurate calculations of electrical and magnetic properties, especially those of importance in nonlinear optics. Since most experiments in this field measure ratios, not absolute values, it is necessary to have a calculated value. Universally, Bishop s helium nonlinear optical properties are used. In the same field, he was the first to seriously investigate the effects of electric fields on vibrational motions, with a much-quoted paper.65 His theory and formulation has now been added to two widely used computational packages HONDO and SPECTROS. He has also derived a rigorous formula to account for the frequency dependence (dispersion) in nonlinear optical properties.66 He used this theory to demonstrate that the anomalous dispersion in neon, found experimentally, is an artifact of the measurements. 

D. M. Bishop,/. Chem. Phys., 90, 3192 (1989). General Dispersion Formulae for Molecular Third-Order Nonlinear Optical Properties. 

In this section the electronic structure of conjugated polymers is discussed. They form a special class of materials with particular types of excitations (such as the solitons) and properties, introduced briefly in Chapter 11. These problems are discussed here essentially in relation to the spectroscopic properties. The related but distinct subject of electrical conductivity is treated in Section IV. To set the scene, we first present some typical results visible absorption and emission spectra and resonance Raman spectra. We consider the theoretical issues in Section III.B, then return to the meaning of the experimental results in Section III.C. The interesting nonlinear optical properties of CPs will be considered in Section III.D. These sections are concerned with electronic states within the gap or near the band edges the structure (i.e., the dispersion relations) of valence and conduction bands is also of theoretical interest and is considered in Section III.E. 

Many interesting phenomena and results can be found studying nonlinear optical properties of one-dimensional photonic crystals. The availability of strong light confinement and tailoring of the dispersive properties allows to design and develop new miniaturized devices for photonic circuitry. 

The linear optical properties of the isomers of 4-[ethyl(2-hydroxy-ethyl) aminoj-4-nitrobenzene (disperse red 1 or DRl) have attracted the attention of researchers for many years, and during the last decade, the nonlinear optical properties of DRl placed in a polymer environment also have been of interest. The trans- and as-isomers of DRl are illustrated in Figure 9.1. Tlie photoisomerization reaction begins by elevating molecules to excited electronic states, followed by nonradiative decay back to the ground slate in either the cis or trans forms, as illustrated in Figure 9.2. TTie ratio of dsUrans states is dependent on the quantum yield of the appropriate photoisomerization reaction (e.g., and for the direct trans= cis and reverse cis= trans photoisomerization reactions, respectively). As the trans-isomer is more stable than the c/s-isomer, molecules in the cis form convert to the trans form bv... 

F. Simoni, Nonlinear optical properties of liquid crystals and polymer dispersed liquid crystals World Scientific, Singapore 1997. 

C. Adant, M. Dupuis, and J. L. Bredas, Int.J. Quantum Chem., Quantum Chem. Symp., 29, 497 (1995). Ab Initio Study of the Nonlinear Optical Properties of Urea Electron Correlation and Dispersion Effects. 

The nonlinear optical properties of polydiacetylenes are subject of an increasing interest in last years (1-4). This is due to the fact that polydiacetylenes are a one-dimensionnal system of higly polarizable conjugated tt elections The polarization depends strongly on electron delocalization length Moreover, the electronic origin of hyperpolarizability implies short response times On the other hand, the wave dispersed measurements of molecular hyperpolarizabilities yield information about forbidden electronic transitions In fact the bulk polarization can be developped in external electric field power series ... 

DAmore E, Di Giulio M., Pietralunga S. M., Zappettini A., Nasi L., Rigato V., and Martinelli M., Sputtered stoichiometric Te02 glass films Dispersion of linear and nonlinear optical properties,/. Appl Phys., 94, 1654-1661 (2003). 

Most theoretical discussions for molecules concentrate on calculations of second-order nonlinear optical properties. These results can be used equally well for the design of either molecules or molecular fragments. The latter are intended for inclusion in polymers as either a solid solution or side-chains. These are discussed in detail in section 4.3, together with systems in which a crystalline phase is dispersed in a polymer matrix. In molecularly dispersed systems the incorporation and orientation of an active species in a polymer obviates the need for a non-centrosymmetric crystal structure but does require the imposition of a polar state on the polymer (e.g. with an applied electric field). Thus molecular species that as crystals are not useful as second-order nlo materials (because they adopt a centrosymmetric structure) may be applicable in a polymeric system. Though it has received less attention in the past, considerable effort has recently been devoted to theoretical studies of... 

Colloidal dispersions of metals, semiconductors, and polymers have attracted considerable interest because of their photochemical [1], photocatalytic [2], and nonlinear optical properties [3]. Various methods for their preparation... 

The theory of nonlinear optical processes in crystals is based on the phenomenological Maxwell equations, supplemented by nonlinear material equations. The latter connect the electric induction vector D(r,t) with the electric field vector E(r, t). In general, the relations are both nonlocal and nonlinear. The property of nonlocality leads to the so-called spatial dispersion of the dielectric tensor. The presence of nonlinearity leads to the interaction between normal electromagnetic waves in crystals, i.e. makes conditions for the appearance of nonlinear optical effects. 

The reaction is conducted the same way as with MWNT with the sole difference of employing toluene instead of DMF as a solvent. This is because the nanotubes present as impurity in the sample are insoluble in toluene, whereas in DMF, they would be dispersed too, and participate in the reaction with the azomethine yiides. In toluene, on the other hand, only fullerenes and onions are sufficiently dispersed. The obtained samples feature interesting nonlinear optics (NLO) properties. In the meantime, one has also succeeded in generating on the onions surface carboxyl groups subsequently to be functionalized by reaction with amines (Figure 4.40). 

---