Poly nonlinear optical effects

Third Order Nonlinear Optical Effects in Vacuum Evaporated Poly-dyacetylene Film Waveguides... 

C). The nonlinear optical effects were studied at 633 nm at room temperature. In another example of substitution reactions of [NPCl2] the sodium salt of 7-(2-hydroxyethoxy)-4-methylcoumarin was used to incorporate photosensitive coumarin groups on the main phosphazene chain to obtain the cross-linkable polymer (190) (average ca. 10, Tg = 67 °C) that is stable up to 280 °C and that, under XJV irradiation, undergoes a [2 -l- 2] cycloaddition to form insoluble cross-linked curable films. The related poly[(bis(3-acetylcoumarin-o-aminoben-zoylhydrazone)phosphazene] has also been reported. ... 

P. N. Prasad and D. J. Williams, Introduction to Nonlinear Optical Effects in Molecules and Poly- 55. 

The linear and nonlinear optical behaviors of poly-(1,6-heptadiyne)s containing NLO chromophores was summarized in Table 22. It was found that n of the copolymers gave higher values than that of poly-76 not bearing any chromophore while the values of Amax were similar to each other. This result clearly shows the effects of incorporation of chromophore into the polymer backbone. The values of electrooptic coefficients, r33, for poled film samples of poly-77 to poly-81 by using a simple reflection technique reported by Teng et al. was measured. Table 22 shows the measured electrooptic coefficients of polymer films at... 

Twieg and coworkers, reported preparation of poly(norbomene) copolymers functionalized with nonlinear optical chromophore side groups. Use was made of (ri -toluene)Ni(C6F5)2, catalyst in the polymerization of norbomene. The nickel complex used to polymerize the norbomene monomers is tolerant to many functional groups found in nonlinear optical chromophores. On the other hand, nitriles and amines other than trisubstituted amines strongly inhibit the reaction. A copolymer of hexylnorbomene and a norbomene-functionalized Disperse Red I chromophore was scaled up and studied in detail. Initial studies indicate that electric field poling is effective but that relaxation of polar order in the poly(norbomene) is faster than in a comparable methacrylate copolymer. The copolymer can be illustrated as follows ... 

J. Y. Huang and his coworkers used SHG to probe the nonlinear optical properties of purple membrane-poly(vinyl alcohol) films [10]. The SHG is attributed to the naturally oriented dipole layers. Recently Alfano and coworkers have also reported SHG from animal tissues [21]. Even though they attributed the SHG only from the surface term that is due to the broken symmetry at the boundary, they also found some SHG intensity dependence on the tissue constitutes with asymmetric structures such as collagen. Combining this effect, they demonstrated SHG tomography for mapping the structure of animal tissues by use of 100-fs laser pulses at 625 nm [33]. 

Nonlinear Optical Applications. Second-order nonlinear (NLO) materials based on ElAPs have shown promise for use in the photonics industry extensive research has been conducted in this area over the past several decades (356,357). Devices based on poly(diacetylene) have been used to demonstrate all-optical switching at 1.6 tm (358). The NLO process occurs when an electromagnetic field interacts with a medium. When the medium is subjected to an electric field E(0) and an optical field E(co), the nonlinear effect arises from field-induced... 

For example, the sergeants and soldiers experiment features a preferential screw-sense helical amplification in optical active copolymers with racemic helical structures named by Green et al. [17,18], This effect means that a small portion of enantiopure chiral side groups determines the overall screw sense (P or M) of the helical main chain bearing a majority of achiral side groups, and a population of helicity with one preferential screw-sense is nonlinearly amplified as a function of the chiral impurity. Since the first report of this phenomenon in poly-a-olefin copolymers by Pino et al. [21],... 

Kauranen, M, et al., Chiral effects in the. second-order optical nonlinearity of a poly(isocyanide) monolayer, Adv. Mater., 7, 641 (1995). 

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