Nonlinear optics second-order applications

L.R. Dalton, A.W. Harper, R. Ghosn, W.H. Steier, M. Ziari, H. Fetterman, Y. Shi, R.V. Mustacich, A.K.Y. Jen, K.J. Shea, Synthesis and Processing of Improved Organic Second-Order Nonlinear Optical Materials for Application in Photonics , Chem. Mater., 7, 1060 (1995)... 

Dalton LR, et al. 1995. Synthesis and processing of improved organic second order nonlinear optical materials for applications in photonics. Chem Mater 7(6) 1060 1081. 

Dalton, L. R., Harper, A. W., Ghosn, R., Steier, W. H., Ziari, W., Fetterman, H., Shi, Y, and Mustacich, R. V., Synthesis and processing of improved organic second-order nonlinear optical materials for applications in photonics, Chem. Mater., 7, 1060-1081 (1995). 

The focus of the present chapter is the application of second-order nonlinear optics to probe surfaces and interfaces. In this section, we outline the phenomenological or macroscopic theory of SHG and SFG at the interface of centrosymmetric media. This situation corresponds, as discussed previously, to one in which the relevant nonlinear response is forbidden in the bulk media, but allowed at the interface. 

The applications of this simple measure of surface adsorbate coverage have been quite widespread and diverse. It has been possible, for example, to measure adsorption isothemis in many systems. From these measurements, one may obtain important infomiation such as the adsorption free energy, A G° = -RTln(K ) [21]. One can also monitor tire kinetics of adsorption and desorption to obtain rates. In conjunction with temperature-dependent data, one may frirther infer activation energies and pre-exponential factors [73, 74]. Knowledge of such kinetic parameters is useful for teclmological applications, such as semiconductor growth and synthesis of chemical compounds [75]. Second-order nonlinear optics may also play a role in the investigation of physical kinetics, such as the rates and mechanisms of transport processes across interfaces [76]. 

Chiral Materials for Second-Order Nonlinear Optical Applications... 

In the following sections we will first in Section 2 briefly discuss the necessary background to understand optical activity effects in linear and nonlinear optics and to illustrate the similarities and differences between both types. In Section 3 we present a more thorough analysis of nonlinear optical effects in second-harmonic generation, both from a theoretical and an experimental point of view. Section 4 deals with experimental examples that illustrate the usefulness of nonlinear optical activity in the study of chiral thin films and surfaces. Finally, in Section 5 we give an overview of the role of chirality in the field of second-order nonlinear optics and show that chiral molecules can be useful for applications in this field. 

CHIRAC MATERIALS FOR SECOND-ORDER NONLINEAR OPTICAL APPLICATIONS... 

Second-order nonlinear optics (NLO) has several applications in the field of optoelectronics.11 Several of these nonlinear processes are straightforward to experimentally demonstrate but their application in devices has been hampered by the lack of appropriate materials. Necessary requirements for second-order nonlinear optical materials include the absence of centrosymmetry, stability (thermal and mechanical), low optical loss, and large and fast nonlinearities.8... 

The study of chiral materials with nonlinear optical properties might lead to new insights to design completely new materials for applications in the field of nonlinear optics and photonics. For example, we showed that chiral supramolecular organization can significantly enhance the second-order nonlinear optical response of materials and that magnetic contributions to the nonlinearity can further optimize the second-order nonlinearity. Again, a clear relationship between molecular structure, chirality, and nonlinearity is needed to fully exploit the properties of chiral materials in nonlinear optics. 

Optical lithography, in compound semiconductor processing, 22 193 Optically active citronellol, 24 506 Optically transparent porous gel-silica, 23 75, 76 Optical materials nonlinear, 17 442-460 second-order nonlinear, 17 444—453 third-order nonlinear, 17 453-457 Optical memory, photochromic material application, 6 602 Optical microscopy, 16 467-487 history of, 16 467-469 in kinetic studies, 14 622 liquid immersion, 15 186 Optical mode density, 14 849, 850-852 Optical multichannel analyzers (OMAs), 23 143... 

Serious attempts to use LB films in commercial applications include the use of lead stearate as a diffraction grating for soft x-rays (64). Detailed discussion on applications of LB films are available (4,65). From the materials point of view, the ability to build noncentrosymmetric films having a precise control on film thickness, suggests that one of the first applications of LB films may be in the area of second-order nonlinear optics. Whereas a waveguide based on LB films of fatty acid salts was reported in 1977, a waveguide based on polymeric LB films has not yet been commercialized. 

This review summarizes the current state of materials development in nonlinear optics. The relevant properties and important materials constants of current commercial, and new, promising, inorganic and organic molecular and polymeric materials with potential in second and third order NLO applications are presented. 

Applications of Organic Second-Order Nonlinear Optical Materials... 

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