The incorporation of active materials
into metasurface
architectures
enhances functionality by enabling active tuning of the electromagnetic
response, a freedom that would be highly beneficial in many applications
at visible frequencies. Here, we employ Li-ion insertion into amorphous
silicon, a traditional battery chemistry, to realize modulation of
visible frequency metasurfaces utilizing both a change in refractive
index and accompanying lattice expansion. We quantify the refractive
index change upon lithiation, achieving Δn =
0.12 at 500 nm and employ the material in a metasurface, demonstrating
reversible color bleaching with accessible intermediate states. This
is achieved at a power consumption of less than 120 μW/cm2. Given the low power consumption and potential for energy
recycling, dynamic electrochemical metasurfaces are uniquely suited
for applications in the visible spectrum that demand small form factor
and low power usage.