Discuss second order non-linear optical (NLO) behaviour in polymers?
Second order nonlinear optical (NLO) materials are important for applications such as optical switching, frequency conversion, and electro-optic modulation. Polarized infrared reflection-absorption spectroscopy is employed as an approach to study the relaxation of the poled order in second order NLO materials using new characterization techniques.
Second order nonlinearity in polymers arises in most cases from the microscopic optical nonlinearity of the chromophores incorporated into the polymer structure. The nonlinear response of these NLO- chromophores is expressed in higher order contributions to the induced dipole moment when the molecule interacts with external electric fields. It follows from symmetry considerations, that noncentrosymmetry is a prerequisite for second order &chi(2)-materials. The ...
This solution provides a discussion of non-linear optical behavior.