Fast switchable grating based on orthogonal photo alignments of ferroelectric liquid crystals

We demonstrate a fast switchable grating based on ferroelectric liquid crystals and orthogonal planar alignment by means of photo alignments. Both 1D and 2D gratings have been constructed. The proposed diffracting element provides fast response time of around 20 mu s, contrast of 7000:1 and high diffraction efficiency, at the electric field of 6V/mu m. The saturated electro-optical (EO) states up to very high frequency (approximate to 5 kHz) are the real advantage of the proposed switchable grating, which opens several opportunities to improve the quality of existing devices and to find new applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737642]