Liquid crystal bubbles forming a tunable micro-lenses array

Cholesteric liquid crystals with long pitch confined in homeotropic cells can be used to generate stable but distorted and localized liquid crystal structures exhibiting spherulitic textures, known as "bubbles." As these bubbles can be induced by an external electric field with a narrow range following the confinement ratio C=d/p approximate to 1 (d representing cell thickness and p representing cholesteric pitch), it is possible to obtain electrically controlled micro-lenses. Here we investigated the optical and electro-optical properties of such liquid crystal bubbles for creating an array of micro-lenses with electrically tunable focal length.