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.