title: Tunable Metasurface and Flat Optical Zoom Lens on a Stretchable Substrate.
abstract: A mechanically reconfigurable metasurface that can continuously tune the wavefront is demonstrated in the visible frequency range by changing the lattice constant of a complex Au nanorod array fabricated on a stretchable polydimethylsiloxane substrate. It is shown that the anomalous refraction angle of visible light at 632.8 nm interacting with the tunable metasurface can be adjusted from 11.4° to 14.9° by stretching the substrate by ∼30%. An ultrathin flat 1.7× zoom lens whose focal length can continuously be changed from 150 to 250 μm is realized, which also demonstrates the potential of utilizing metasurfaces for reconfigurable flat optics.
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ho-Seok
authors.initials: HS
authors.lastname: Ee
authors.affiliation: Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Agarwal
keywords: Metasurface; flat lens; flat optics; flat zoom lens; reconfigurable metasurface; tunable metasurface