Tiny hologram inside a fiber lets scientists control light with incredible precision

Researchers in Germany have unveiled the Metafiber, a breakthrough device that allows ultra-precise, rapid, and compact control of light focus directly within an optical fiber. Unlike traditional systems that rely on bulky moving parts, the Metafiber uses a tiny 3D nanoprinted hologram on a dual-core fiber to steer light by adjusting power between its cores. This enables seamless, continuous focus shifts over microns with excellent beam quality.