Ultra-Sensitive, Mechanically-Responsive Optical Metasurfaces via Strain Amplification.

Optical metasurfaces promise a new generation of ultrathin, lightweight, miniaturized optical components with unprecedented capabilities to manipulate light compared to conventional, bulk optics. The emergence of reconfigurable metasurfaces further integrates dynamic tunability with optical functionalities. Here, we report a structurally-reconfigurable, optical metasurface constructed by integrating a plasmonic lattice array in the gap between a pair of symmetric microrods that serve to locally amplify the strain created on an elastomeric substrate by an external mechanical stimulus. The strain on the metasurface is amplified by a factor of 1.5 to 15.9 relative to the external strain by tailoring the microrod geometry. For the highest strain amplification geometry, the mechano-sensitivity of the optical responses of the plasmonic lattice array is a factor of 10 greater than that of state-of-the-art stretchable plasmonic resonator arrays. The spatial arrangement and therefore the optical response of the plasmonic lattice array is reversible showing little hysteresis.