title: Large-area flexible 3D optical negative index metamaterial formed by nanotransfer printing.
abstract: Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials. Recent work has demonstrated that focused ion beam and layer-by-layer electron-beam lithography can be used to pattern the necessary nanoscale features over small areas (hundreds of µm(2)) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for 'inking' it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75 cm(2)) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit.
authors.affiliation: Department of Materials Science, Beckman Institute, and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Debashis
authors.initials: D
authors.lastname: Chanda
authors.forename: Kazuki
authors.initials: K
authors.lastname: Shigeta
authors.forename: Sidhartha
authors.initials: S
authors.lastname: Gupta
authors.forename: Tyler
authors.initials: T
authors.lastname: Cain
authors.forename: Andrew
authors.initials: A
authors.lastname: Carlson
authors.forename: Agustin
authors.initials: A
authors.lastname: Mihi
authors.forename: Alfred J
authors.initials: AJ
authors.lastname: Baca
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Bogart
authors.forename: Paul
authors.initials: P
authors.lastname: Braun
authors.forename: John A
authors.initials: JA
authors.lastname: Rogers