Brownian Motors in the Photoalignment of Liquid Crystals: Simulations

Abstract In the photoalignment of liquid crystals with dissolved dyes or in the presence of dye doped alignment layers, light can cause reorientation of the liquid crystal director against a restoring elastic torque essentially without the transfer of angular momentum. We show that this phenomenon originates in an orientational ratchet mechanism, where, under photoexcitation, the dye molecules act as rotors of a Brownian motor.