Applications of NLO polymers

The application potential of the effects dealt with in this chapter covers a broad field extending from specific electro-optical devices to the all-optical computer. For many applications, polymeric materials have proven appropriate and equivalent to inorganic materials. This section is focused on two aspects, the electro-optical (EO) or Pockels effect and two-photon absorption, which have been exploited extensively. Technical developments relating to polymeric modulators operating on the basis of the Pockels effect have reached the stage of commercialization [5]. 

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Looking further towards applications of coordination polymers, Lin and coworkers have demonstrated that polar solids (with substantial NLO response) can be designed through an appropriate choice of polar bridging ligands combined with tetrahedral metal centres that provide acentric nodes [140], Chiral separations [141] and modest catalytic activity [141,142] have also been demonstrated in coordination polymers. 

In this chapter, the development of NLO polymers with thin film or channel waveguide structures directed toward practical optical devices will be discussed. All optical signal processing polymers and electro-optical polymers are presented. Hybrid polymer optical devices for future applications will also be presented. 

Future Targets of NLO Polymers for Optical Device Applications... 

Other applications of nlo LB polymers include their use as optical filters. An optical filter consists of sequential stacks of at least two materials of different refractive index deposited on top of one another. While inorganic materials have largely been used for such devices, for... 

This chapter describes the physical and chemical basis for the development of nlo polymers. To achieve a fast response, the nlo properties must derive from electronic excitation of active molecular species. Progress towards an understanding of structure-property relationships for these has resulted from the development of tractable quantum mechanical models. These have resulted in general rules helpful in the development of synthetic routes to molecules with large nlo coefficients. Additional constraints come into play if a technologically useful material is to be obtained. These can be further refined in the context of the device structure relevant to particular end applications. These considerations are discussed in the following section. The development of polymers with particular nlo properties is presented in the subsequent sections. 

The previous section showed how the design of nlo polymers has evolved from the successful understanding and application of the molecular design of low-molecular-weight crystalline materials. 

Finally, it should be mentioned that often solids are more desirable than liquids in typical applications of films. The prospects for obtaining polymer films with useful thermodynamically stable %(2) seems high given the recent demonstration that functional group orientation in FLC side chain polymers appears very similar to that observed for the low molecular weight materials (IQ). The fact that FLC polymers possess thermodynamically stable polar order in a non-crystalline solid film would appear to make this novel type of polymer glass uniquely suited for many second order NLO applications. 

This chapter gives an overview of the origin of NLO effects and focuses on the design of chromophores for two current applications of technological interest poled polymer materials for electrooptic switching and two-photon absorption. 

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