Synthesis Nonlinear optics

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]. 

Optically active polymers are potentially very useful in areas such as asymmetric catalysis, nonlinear optics, polarized photo and electroluminescence, and enantioselective separation and sensing.26 Transition metal coupling polymerization has also been applied to the synthesis of these polymers.27 For example, from the Ni(II)-catalyzed polymerization, a regioregular head-to-tail polymer 32 was obtained (Scheme 9.17).28 This polymer is optically active because of the optically active chiral side chains. 

In the field of polymer chemistry the regio- and stereoselectivity of the Diels-Alder reaction is used for the concerted synthesis of structurally homogeneous double-stranded ladder polymers [39], which are useful materials with nonlinear optical properties and high electrical conductivity. It has turned out that the repeated Diels-Alder method is superior to an alternative two-step process, in which first an open chain precursor is formed followed by polymer ring closure as structural defects can occur [40]. 

Much of the work presented in this chapter represents a synergistic effort from several complementary research fields quantum-chemical theory, chemical synthesis, and nonlinear optical materials characterization. This combination of expertise... 

Chiang, W. Thompson, M. E. Van Engen, D. Synthesis and Nonlinear Optical Properties of Inorganic Co-ordination Polymers. In Organic Materials for Nonlinear Optics II Hann, R. A., Bloor, D., Eds. Royal Society of Chemistry London, 1991 pp 210-216. 

A synthesis and physicochemical characterization, including molecular second-order nonlinear optical properties, of new push-pull-based chromophores 170 properly functionalized for polymerization and containing oxadiazole rings were reported <2002J(P2)1791>. 

Let us consider the crystal growth of the three previous compounds which have retained our attention by their high nonlinear optical susceptibilities (POM, MAP, NPP) plus an additional one R(+)N-methylidene (gem-carbethoxiphenyl) amide of 4-N-dime-thylamino- benzylidene cyanacetlc acid -AMA, of potential interest but not yet investigated from the optical point of view. We look successively into their synthesis, purification, crystal growth and characterization. 

Molecularlv Doped Thermotropic Liquid Crystalline Polymer. The idea of the nonlinear optical medium which is the subject of this paper results from a synthesis of the ideas of the discussion above and a few concepts from nonlinear optical molecular and crystal physics. As discusssed several places in this volume, it is known that certain classes of molecules exhibit tremendously enhanced second-order... 

We first discuss the materials research which includes monomer synthesis, growth of monomer crystalline structures and polymerization in the solid state, yielding the requisite polymer structures. Next, the nonlinear optical experimental research is discussed which includes a novel experimental technique to measure x (w). Linear and nonlinear optical data obtained for the polydiacetylene films is subsequently presented. Detailed theoretical analysis relating the data to x (< >) and subsequently to its molecular basis will be discussed in a later publication. 

Linear and nonlinear optical properties of a class of polydiacetylenes that can be grown as large area and controlled thickness thin films have been investigated. This involved an integrated research effort including monomer synthesis, thin film growth and new measurement techniques. 

The driving force in polymer synthesis is the search for new polymers with improved properties to replace other materials of construction. Polymers are lightweight and can be processed easily and economically into a wide range of shapes and forms. The major synthetic efforts at present are aimed at polymers with high temperature, liquid crystal, conducting, and nonlinear optical properties [Maier et al., 2001 Sillion, 1999]. There is an interrelationship between these efforts as will become apparent. 

Huggins KE, Son S, Stupp SI. Two-dimensional suptamolecular assemblies of a polydiacetylene. 1. Synthesis, structure, and third-order nonlinear optical properties. Macromolecules 1997 30 5305-5312. 

The 2PA research in our group began in 1996, involving a number of facets, from fundamental to applications. This review summarizes about 10 years of research efforts on 2PA materials and appHcations in our group. The first section includes the design and synthesis of novel 2 PA chromophores and the chemistry involved in their preparation. The second section is concerned with the linear and nonlinear optical properties of these chromophores as well as their photodynamic behavior. In the last section, further optimization of the chromophores for several intriguing applications is discussed, as are the principles of these applications. 

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