Tunable Optical Grating Based on the Flexoelectric Effect in a Bent-Core Nematic Liquid Crystal
AbstractOptical gratings are created by flexoelectric domains in a bent-core nematic liquid crystal. A unique feature of this structure is that its wavelength can be controlled by the amplitude of the applied voltage, as demonstrated by polarizing microscopy and light diffraction techniques. In order to understand the reaction of the system to the voltage change, the dynamics of the switching process is studied via digital processing of recorded image sequences. It is shown that the characteristics and the switching mechanisms are different if the lower voltage level is below or above the threshold of pattern onset. In both cases, the response to increasing voltage levels is much slower than the response to decreasing voltage levels.