title: High-Throughput Fabrication of Resonant Metamaterials with Ultrasmall Coaxial Apertures via Atomic Layer Lithography.
abstract: We combine atomic layer lithography and glancing-angle ion polishing to create wafer-scale metamaterials composed of dense arrays of ultrasmall coaxial nanocavities in gold films. This new fabrication scheme makes it possible to shrink the diameter and increase the packing density of 2 nm-gap coaxial resonators, an extreme subwavelength structure first manufactured via atomic layer lithography, both by a factor of 100 with respect to previous studies. We demonstrate that the nonpropagating zeroth-order Fabry-Pérot mode, which possesses slow light-like properties at the cutoff resonance, traps infrared light inside 2 nm gaps (gap volume ∼ λ(3)/10(6)). Notably, the annular gaps cover only 3% or less of the metal surface, while open-area normalized transmission is as high as 1700% at the epsilon-near-zero (ENZ) condition. The resulting energy accumulation alongside extraordinary optical transmission can benefit applications in nonlinear optics, optical trapping, and surface-enhanced spectroscopies. Furthermore, because the resonance wavelength is independent of the cavity length and dramatically red shifts as the gap size is reduced, large-area arrays can be constructed with λresonance ≫ period, making this fabrication method ideal for manufacturing resonant metamaterials.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Daehan
authors.initials: D
authors.lastname: Yoo
authors.affiliation: Department of Aeronautics and Astronautics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Ngoc-Cuong
authors.initials: NC
authors.lastname: Nguyen
authors.affiliation: Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza , E-50009 Zaragoza, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martin-Moreno
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Mohr
authors.affiliation: Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla , 41092 Sevilla, Spain.
authors.forename: Sol
authors.initials: S
authors.lastname: Carretero-Palacios
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Jonah
authors.initials: J
authors.lastname: Shaver
authors.affiliation: Department of Aeronautics and Astronautics, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States.
authors.forename: Jaime
authors.initials: J
authors.lastname: Peraire
authors.affiliation: ISIS, University of Strasbourg and CNRS , 67000 Strasbourg, France.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Ebbesen
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Oh
mesh_terms: D006046:Gold / Q000737:chemistry*; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D055095:Optics and Photonics
chemical_list: D006046:Gold
keywords: Coaxial nanohole; atomic layer lithography; epsilon-near-zero metamaterial; extraordinary optical transmission; glancing-angle ion milling; slow light