Second-order organic nonlinear optical

A crucial objective of research involving second order organic nonlinear optical materials is the realization of polymeric electro-optic waveguides characterize by... 

The device performance of any application in the real world has to be guaranteed for a certain time without or only minor degradation. Some 10,000 hours of operation at temperatures up to 80 °C under illumination are required. Research about the lifetime of organic nonlinear optical material has only started in the past years as the chances for applications based on the second-order susceptibilities x have improved. Nevertheless, only little is known about the longtime effects in nonlinear materials under real world conditions. 

One of the most obvious application of second order organic materials is the fabrication of electro-optic modulators for high frequency communication applications. Such applications permit not only exploitation of the large optical nonlinearity realized with... 

Recent development of organic nonlinear optical (NLO) polymers has focused on the fabrication of thermally stable NLO materials in which the second order nonlinearity... 

In summary, we have briefly reviewed current research highlights from studies of second order nonlinear optical responses in organic and polymeric media. We have stressed how fundamental studies have led to microscopic understanding of important electronic states that comprise the origin of the large second order nonlinear responses in these... 

Over the past decade it has been learned that organic materials containing appropriately constituted or substituted conjugation systems may exhibit highly enhanced electronic nonlinear optical polarization responses Since the microscopic second-order... 

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. 

In Equation 6, n (a>.) is the intensity independent refractive index at frequency u).,.0 Tlie sum in Equation 5 is over all the sites (n) the bracket, < >, represents an orientational averaging over angles 0 and . Unlike for the second-order effect, this orientational average for the third-order coefficient is nonzero even for an isotropic medium because it is a fourth rank tensor. Therefore, the first step to enhance third order optical nonlinearities in organic bulk systems is to use molecular structures with large Y. For this reason, a sound theoretical understanding of microscopic nonlinearities is of paramount importance. 

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