Third-harmonic generation , nonlinear polymer applications

This article introduces the field of nonlinear optics and the electronic nonlinear optical (NLO) response of polymers and pol5mier composites. Both second- and third-order NLO phenomena are included, with primary emphasis on harmonic generation, the intensity-dependent refractive index, and nonlinear (multiphoton) absorption effects. The beginning sections introduce the phenomena and explain how the order of the nonlinearity can be understood from a series expansion of the polarization in powers of the electric-field. In addition to listing the variety of nonlinear optical phenomena and some applications, some of the advantages of polymeric materials for NLO applications are also surveyed. 

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