Acentric chromophore lattices

B. Generation of Acentric Chromophore Lattices by Electric Field Poling... 

To satisfy device-related materials requirements, chromophores must exhibit large molecular hyperpolarizabilities and must be incorporated in Mgh number density into thermally stable acentric chromophore lattices defined by a high degree of chromophore order. Realization of approximately 10% of the potential macroscopic optical nonlinearity of a chromophore requires chromophore loading on the order of... 

Since 1990, self-assembly techniques involving covalent linkages and layer-by-layer fabrication were reported to yield robust noncentric super lattices highly suited for applications such as SHG and electro-optic effects. " Spontaneous and sequential adsorption of appropriately derivatized adsorbates onto substrates in a self-limiting fashion can yield thin films with uniform polar orders in individual layers. This represents an attractive approach to the construction of intrinsically acentric chromophoric super lattices. Li et reported synthetic routes to the... 

Fig. 5. Second harmonic generation is shown as a function of temperature for heating at a rate of 10°C per minute for two samples. The uncross-linked sample (chromophore is attached covalently by one end to a PMMA backbone) starts to lose second-order optical nonlinearity (acentric chromophore order) before 100°C. The cross-linked sample corresponds to both ends of the chromophore being covalently coupled to the pol3maer lattice. For this sample, thermally stable second-order optical nonlinearity is observed imtil nearly 170°C.

---