Electrochemically mutable soft metasurfaces

Siddharth Doshi; Anqi Ji; Ali I Mahdi; Scott T Keene; Skyler P Selvin; Philippe Lalanne; Eric A Appel; Nicholas A Melosh; Mark L Brongersma

doi:10.1038/s41563-024-02042-4

Electrochemically mutable soft metasurfaces

Nat Mater. 2024 Nov 13. doi: 10.1038/s41563-024-02042-4. Online ahead of print.

Authors

Siddharth Doshi^{1

2}, Anqi Ji¹, Ali I Mahdi^{1

2}, Scott T Keene^{3

4}, Skyler P Selvin¹, Philippe Lalanne⁵, Eric A Appel², Nicholas A Melosh⁶, Mark L Brongersma^{7

8}

Affiliations

¹ Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA.
² Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
³ Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, UK.
⁴ Cavendish Laboratory, University of Cambridge, Cambridge, UK.
⁵ LP2N, University of Bordeaux, IOGS, CNRS, Talence, France.
⁶ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. nmelosh@stanford.edu.
⁷ Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA. brongersma@stanford.edu.
⁸ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. brongersma@stanford.edu.

PMID: 39537748
DOI: 10.1038/s41563-024-02042-4

Abstract

Active optical metasurfaces, capable of dynamically manipulating light in ultrathin form factors, enable novel interfaces between humans and technology. In such interfaces, soft materials bring many advantages based on their flexibility, compliance and large stimulus-driven responses. Here, we create electrochemically mutable, soft metasurfaces that capitalize 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 substantial tuning and low optical loss that is intrinsic to dynamic metasurfaces relying on index tuning of materials. Using the commercial polymer PEDOT:PSS, we demonstrate dynamic, high-resolution colour tuning and high-diffraction-efficiency (>19%) beam-steering devices that operate at CMOS-compatible voltages (~1.5 V). These results highlight how the deformability of soft materials can enable a class of high-performance metasurfaces that are suitable for body-worn technologies.