Flexoelectro-optic effect in a hybrid nematic liquid crystal cell

We analyse the influence of charged impurities and flexoelectric polarizati on on the optical transmission of a hybrid aligned nematic liquid crystal c ell. The theoretical results obtained within the framework of the Poisson-B oltzmann equation and Frank elastic theory are compared with the observed o ptical response [N. V. Madhusudana and G. Durand, J. Phys. Lett. 46, L-195 (1985)]. We show that impurities can be very important for the behaviour of the system in the low field regime where the flexoelectric effect is relev ant, and we determine the flexoelectric coefficient, the anchoring strength , and the concentration of impurities in the sample previously studied by M adhusudana and Durand.