Photorefractive chiral smectic A phases

We present results of the photorefractive properties of a chiral smectic A liquid-crystalline phase. In our approach, the mesophase is sandwiched betw een two photoconducting layers. In contrast to the effect due to the dielec tric anisotropy typical of nematic phases, the refractive-index modulation is due to the electroclinic effect. We measured the grating spacing and the field dependence of the gain coefficient and obtained a net two-beam coupl ing gain of 600 cm(-1) at 35 V/mum. (C) 2001 American Institute of Physics.