Langmuir Blodgett films, nonlinear optical

Bosshard, C., Kniipfer, M., Fldrsheimer, M., and Gunter, P., Nonlinear optical effects in 2-docosylamino-5-nitropyridine and other Langmuir-Blodgett films. Nonlinear Opt., 3, 215-231 (1992). 

Nonlinear Optical Properties of Langmuir-Blodgett Films Containing C60 and Derivatives... 

As this volume attests, a wide range of chemistry occurs at interfacial boundaries. Examples range from biological and medicinal interfacial problems, such as the chemistry of anesthesia, to solar energy conversion and electrode processes in batteries, to industrial-scale separations of metal ores across interfaces, to investigations into self-assembled monolayers and Langmuir-Blodgett films for nanoelectronics and nonlinear optical materials. These problems are based not only on structure and composition of the interface but also on kinetic processes that occur at interfaces. As such, there is considerable motivation to explore chemical dynamics at interfaces. 

Ashwell GJ, Robinson BJ, Amiri MA, Locatelli D, Quici S, Roberto D (2005) Dipole reversal in Langmuir-Blodgett films of an optically nonlinear dye and its effect on the polarity for molecular rectification. J Mater Chem 15 4203-4205... 

In this section, the experimental techniques described in the previous section are applied to the study of thin Langmuir-Blodgett films of chiral molecules and polymers. We will show in detail how the second-order susceptibility of chiral thin films can be analyzed and discuss the influence of chirality on the nonlinear optical response of these films. 

The material system is a Langmuir-Blodgett film of the S enantiomer of a chiral polymer deposited on a glass substrate. The polymer is a poly(isocyanide)30 functionalized with a nonlinear optical chromophore (see Figure 9.14). In this particular system the optical nonlinearity and chirality are present on two different levels of the molecular structure. The chirality of the polymer is located in the helical backbone whereas the nonlinearity is present in the attached chromophores. Hence, this opens the possibility to optimize both properties independently. 

Amino-5-nitropyrimidine, cocrystallization, 455 Amorphous polymers, criteria for use in second harmonic generation, 250-251 Amphiphilic molecules polar Z-type Langmuir-Blodgett films, formation, 473-479 structures, transfer behavior, and contact angles, 474,476-477r Anharmonic oscillator models, nonlinear optical effect-microstructure relationship, 361... 

Ashwell, G.J. (1999) Langmuir-blodgett films Molecular engineering of noncentrosymmetric structures for second order nonlinear optical applications. Journal of Materials Chemistry, 9, 1991-2003. 

Since the first nonlinear susceptibility is a third-rank tensor, it is only non-zero in non-centrosymmetric media. To break the centrosymmetry of the macroscopic media, poling techniques using optical and electric fields have been developed, or use was made of the inherent polar ordering in Langmuir-Blodgett films and crystals with non-centrosymmetric point groups. 

On a conceptual level, the ideal format for thin-film materials for nonlinear optics is the Langmuir-Blodgett film. Molecularly engineered chrom-ophores with large hyperpolarizabilities can, in principle, be incorporated at high concentration, with well-defined orientations into films having thicknesses defined by molecular resolution. Extremely large resonantly enhanced values of have been reported in LB films several layers thick (30, 3i) thus the considerable promise of this approach is established. 

Langmuir-Blodgett films for second-order nonlinear optics, Proc. SPIE 1560 377 (1991). 

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