Diffractive properties of liquid crystal composite gratings

Summary form only given. We present the results of an experimental study of the diffractive properties of liquid-crystal-filled composite gratings. These gratings can be used as high contrast, electrically switchable, diffractive elements for the visible and near infrared. In the study we have found that the refractive index modulation and hence the diffraction efficiency is enhanced over what is theoretically predicted based on measurements of the diffractive properties of the grating before and after it is filled with the liquid crystal.