The Flexoelectrooptic Effect

P. Rudquist, The Flexoelectrooptic Effect in Cholesteric Liquid Crystals, PhD Thesis, Chalmers University of Technology, Goteborg, 1997. 

The flexoelectrooptic effect is a field-sensitive electrooptic effect (it follows the sign of the field), which is fast (typically 10-100 p.s response time) with two outstanding characteristics. First, the induced tilt (p has an extremely large region of linearity, i.e., up to 30° for materials with dielectric anisotropy Ae=0. Second, the induced tilt is almost temperature-independent. This is illustrated in Fig. 39 for the Merck cholesteric mixture TI 827, which has a temperature-independent pitch but not designed or optimized for the flexoelectrooptic effect in other respects. 

Figure 39. The flexoelectrooptic effect measured on the Merck mixture TI 827. (a) Induced tilt as a function of E. (b) Induced tilt as a function of temperature.

The flexoelectrooptic effect belongs to a category of effects that are linear in the electric field, and which all have rather similar characteristics. These include the electroclinic effect, the deformed helical mode in the C phase, and the linear effect in anti-... 

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