Widely tunable large area thin liquid crystals lens

Reconfigurable diffractive lenses manufactured in liquid crystal are presented. The lenses show an unprecedented performance in terms of active diameter and focal distance range when compared to any other transparent adaptive lens. The lenses are characterized by an active area free of electronic components, with a fill factor of 98% which combined with a low operating voltage (<10V(rms)), open for applications ranging from eye contact lenses to space applications. The addressing of the liquid crystal is done exclusively from the periphery of the device. The lenses are based on tunable spiral diffractive lenses (SDL) for which the focal length may be changed by changing the topological charge, i.e. twist of the spiral in the lens. The twist in the resulting wavefront is eliminated by cascading two spiral plates with opposite twists emulating a conventional diffractive lens. The presented lenses have a tuning range from -2 to +2 diopters and an active diameter of 25mm.