Ferroelectric liquid crystals for fast switchable circular Dammann grating [Invited]

Diffractive optical elements attract a considerable amount of attention, mainly due to their potential applications in imaging coding, optical sensing, etc. Application of ferroelectric liquid crystals (FLCs) with photoalignment technology in diffractive optical elements results in a high efficiency and a fast response time. In this study we demonstrate a circular Dammann grating (CDG) with a diffraction efficiency of 84.5%. The achieved response time of 64 Its is approximately two orders of magnitude faster than the existing response time of nematic liquid crystal devices. By applying a low electric field (V= 6 V) to the FLC CDG, it is switched between the eight-order diffractive state and the transmissive diffraction-free state.