This flat chip uses twisted light to reveal hidden images

Scientists have developed a new method to control the interaction of light with chiral structures using metasurfaces. These 2D lattices of tiny elements can tune their chiral properties by varying the orientation of meta-atoms, allowing precise control over polarized light interactions. The innovation has potential applications in data encryption, biosensing, and quantum technologies, as demonstrated by a dual-layer watermark experiment using invisible mid-infrared light.