Second-order nonlinear optical orientation

Kajzar, F, Lee, K.-S. and Jen, A. K.-Y Polymeric Materials and their Orientation Techniques for Second-Order Nonlinear Optics. Vol. 161, pp. 1-85. 

Molecular Design for Enhanced Electric Field Orientation of Second-Order Nonlinear Optical... 

However, non-centrosymmetry does not automatically imply a dipolar molecule, or, more generally, vectorial properties. Also molecules without a dipole moment can exhibit second-order nonlinear optical properties. Tetrahedral molecules, such as CC14, and trigonal molecules, such as BC13, also lack centrosymmetry. However, they cannot be oriented in an electric field, due to the absence of a dipole moment. Therefore, they can simply not be measured by EFISHG. Also ionic species cannot be measured, since these migrate, rather than rotate, under the influence of an applied field. 

Singer, K. D., Kuzyk, M. G., and Sohn, J. E. (1987). Second-order nonlinear-optical processes in orientationally ordered materials relationship between molecular and macroscopic proper-ncN. J. Opt. Soc. Am. B 4, 968-976. 

A number of spectroscopic techniques have already been discussed in Volume 1 (secs. 7.11-13). Here, we will focus on the application of vibrational (infrared and Raman) and UV/visible spectroscopy, fluorescence and second-order nonlinear optical techniques for the study of monolayers. The type of information obtained with these techniques refers to the chemical composition, surface coverage, molecular conformation and orientation, and dynamics of monolayers. 

Polymeric Materials and their Orientation Techniques for Second-Order Nonlinear Optics... 

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