Shaping Light with Soft Electrochemically Mutable Metasurfaces

Active optical metasurfaces, capable of dynamically manipulating light in ultra-thin form factors, could enable novel interfaces between humans and technology. For example, miniaturized devices that actively shape light could open new approaches to biological light delivery for endoscopic imaging and optogenetic stimulation. In such interfaces, soft materials bring many advantages based on their flexibility and large stimuli-driven responses.

Here, we create electrochemically-mutable, soft metasurfaces that capitalise on the swelling of soft conducting polymers to alter the shape and associated resonant response of metasurface elements. Such geometric tuning overcomes the typical trade-off between achieving significant tuning and low optical loss, intrinsic to dynamic metasurfaces that rely on index-tuning of materials. Using the commercial polymer, PEDOT:PSS, we demonstrate dynamic, high-resolution colour-tuning and high-diffraction-efficiency (>19%) beamsteering devices that operate at CMOS compatible voltages (~1.5V). These results highlight how the deformability of soft materials can enable a new class of high-performance metasurfaces that could serve as building blocks for future body-worn technologies.