A layer once dismissed as mere support has transformed a tiny photonic chip into a powerful generator of new light frequencies.

A laser usually produces one narrow color of light. A device small enough to sit on a fingertip can turn that single input into hundreds of precisely spaced frequencies, creating a tool for measuring time, identifying chemicals, transmitting data, and studying distant objects in space.

Researchers have now expanded what such photonic chips can do by making two of their materials work together. Instead of treating the outer layer as simple packaging, the team used it to generate additional light frequencies that the chip’s main material could not efficiently produce on its own.