Liquid crystals open new route to planar optical elements

Researchers have developed a technology to control the light wavefront reflected from a cholesteric liquid crystal — a liquid crystal phase with a helical structure. Although known for their ability to Bragg-reflect light, cholesteric liquid crystals could only be used as flat mirrors, reflecting light at the same angle as the incident angle. The new technology enables planar optical components to be made with functionality by design, contributing to the miniaturization of catoptrics devices.