Non-resonant light-induced chirality in non-chiral nematic liquid crystals

We propose a simple experimental technique to carry out the observation of light-induced stationary, precessing and oscillating quasi-macroscopic chiral structures of molecular orientation in non-chiral nematics. Moreover, the optical control of these chiral structures is demonstrated both in time and space, using two incoherent counter-propagating circularly polarized excitation beams. Finally, the relaxation of those orientational structures is also investigated and experimental results are shown to be in good agreement with the theory. (C) 2001 Elsevier Science B.V. All rights reserved.