Molecular Structure on Isotropic Phase Reorientational Nonlinearities

Influence of Molecular Structure on Isotropic Phase Reorientational Nonlinearities 

As explained in Chapter 1, molecular structures dictate the inter- and intramolecular fields, which in turn influence all the physical properties of the liquid crystals. 

Molecular structures therefore are expected to influence the reorientational optical nonlinearities in both their magnitude and response time. The study by Madden et al. has shed some light on this topic. 

In the transient degenerate four-wave mixing study (see Chapter 11) conducted by these workers, the observed optical nonlinearity associated with molecular reorientation can be expressed in terms of the parameter 

Note that in Equation (8.31) the / A j terms contribute only when there is a correlation between the orientation of different molecules. Molecular orientational correlation in liquid crystals affects both the amplitude of C(0, k) and its relaxation behavior. 

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