Metasurfaces—ultrathin optical structures that manipulate light—have been proposed as compact alternatives to conventional lenses, mirrors, and filters. Researchers have shown that they can shape, steer, and transform light in ways that would otherwise require much larger optical systems. Yet a major challenge has limited their wider adoption: once a metasurface is fabricated, its functionality is largely fixed. Changing its optical properties often requires designing and manufacturing an entirely new device.

Researchers recently demonstrated a different approach: a pr…