Third-order nonlinear optical properties polymers

Optical properties of cyanines can be usefiil for both chiral substituents/environments and also third-order nonlinear optical properties in polymer films. Methine-chain substituted die arbo cyanines have been prepared from a chiral dialdehyde (S)-(+)-2-j -butylmalonaldehyde [127473-57-8] (79), where the chiral properties are introduced via the chiral j -butyl group on the central methine carbon of the pentamethine (die arbo cyanine) chromophore. For a nonchiral oxadicarbocyanine, the dimeric aggregate form of the dye shows circular dichroism when trapped in y-cyclodextrin (80). Attempts to prepare polymers with carbocyanine repeat units (linked by flexible chains) gave oligomers with only two or three repeat units (81). However, these materials... 

Model Polymers with Distyrylbenzene Segments for Third-Order Nonlinear Optical Properties... 

Conjugated polymers satisfy these requirements and have thus emerged as the most widely studied materials for their susceptability. Some of the examples of conjugated polymers, that have been studied for their third order NLO properties, are polydiacetylenes, poly-p-phenylenevinylenes and polythiophenes. However, CVD has only been used in the case of poly-p-phenylenevinylenes (PPV) [section 3.4], although values have not been reported. An excellent review of third order nonlinear optical properties of PPV in general, can be found in literature. Recently, McElvain et al. ° reported the values of CVD polyazomethines to be... 

Aniline and its derivatives were oxidatively polymerized by peroxidase catalyst. HRP catalyzed the polymerization of aniline in aqueous organic solvents to produce the polymer with a complicated structure in low yields.65 The resulting polymer showed good third-order nonlinear optical properties.66... 

Osaheni and Jenekhe reported a synthesis of conjugated rigid-rod polymers and their NMR data. The conjugated rigid-rod polymers have interesting photoconductive, light-emitting and third-order nonlinear optical properties that have some potential for applications in optoelectronics and photonics. 

Kajzar F, Charra F, Nunzi JM, Raimond P, Idiart E, Zagorska M (1995) Third-order nonlinear optical properties of functionalized polymers. In Prasad PN (ed) Proceedings of international conference on frontier of polymers and advanced materials, Plenum Press, New York, p 141... 

The intensity of the DFWM signal for the poly(l,6-heptadiyne)s increased linearly with intensity of the incident beam, as shown in Figure 10. From the direct comparison between the intercepts of the V axis of the polymers and the carbon disulfide reference. the values of the polymers were obtained. And also, as the concentration of the polymer solution was increased, the values of the polymers were increased (Figure 11). The third-order nonlinear optical properties were enhanced with an increase in the bulk of the substituents at the 4-position, which is in accord with the bathochromic shift of Amax in the UV—vis spectra. From these results, it was concluded that the incorporation of bulky substituents into the 4-position of 1,6-heptadiynes enforces the TT-conjugated polyene into the more planar conformation. resulting in a red shift and the increment of the values of the polymers. Recently, Schrock... 

The polymers having delocalized r-electron in the main chain have been expected to possess extremely large third-order optical susceptibility.However, such an extended jr-electron conjugation generally rendered the polymers insoluble and infusible as well, which has seriously limited the fabrication of practical NLO devices. Recently, it was reported that the third-order nonlinear optical properties of poly(l,6-heptadiyne)s which were environmentally stable, soluble, and processable. The third-order optical nonlinearities of poly(l,6-heptadiyne)s bearing NLO active chomophores were evaluated for the first time. The third-order nonlinear susceptibility... 

THIRD ORDER NONLINEAR OPTICAL PROPERTIES OF FUNCTIONALIZED POLYMERS... 

The third order nonlinear optical properties of the functionalized polymers have been studied by optical third harmonic generation and by four wave mixing. The four wave mixing experiments performed at 1. 064 pm fundamental wavelength reveal index grating writing through trans-cls isomerization via a two photon process. This process can be used for all optical orientation of chromophores, as it will be discussed later. 

The third order nonlinear optical properties of monomers, polymers and copolymers were measured by DFWM in solution. The solutions of these materials were prepared in a solvent mixture of dimethyl formamide and methanol in the ratio 4 1 (v/v) at a concentration of 0.1% (w/v). The solvent mixture DMF MeOH (4 1) was used as a control. Measurements under identical conditions were made with carbon disulfide as the reference standard and this compound has a reported x value of 6.8 x 10 i3 esu (19). The schematic of the experimental setup is shown in Figure 2. 

Many metal polyynes have third-order nonlinear optical properties and these polymers are of interest from the point of view of new types of optical devices. Other types of potential applications of these polymers include light-emitting diodes, lasers, photoeells, field-effect transistors, low-dimensional conductors etc. [70]. 

TABLE 2 Third-Order Nonlinear Optical Properties of Polymers Synthesized in Monophasic Media and Other NLO Samples... 

Table 3 gives the third-order nonlinear optical properties of bioengineered polymers prepared by enzyme-catalyzed polymerization using horseradish peroxidase in biphasic solvent systems. Water-immiscible solvents used for the biphasic media are benzene, chloroform, toluene, tetrahydrofuran, and isooctane. Third-order nonlinear optical properties of homopolymers and copolymers prepared in biphasic solvent systems are similar to those of polymers prepared in monophasic systems. The values of polyaromatic amines solutions measured at 532 nm are one to two orders higher than the x values observed with polyphenolic compounds. Third-order nonlinear optical properties of copolymers of aromatic amines with... 

Bubek, C., Relationship between structure and third-order nonlinear optical properties of conjugated polymers. Nonlinear Opt., 10, 13-22 (1995). 

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