title: Negative refraction in semiconductor metamaterials.
abstract: An optical metamaterial is a composite in which subwavelength features, rather than the constituent materials, control the macroscopic electromagnetic properties of the material. Recently, properly designed metamaterials have garnered much interest because of their unusual interaction with electromagnetic waves. Whereas nature seems to have limits on the type of materials that exist, newly invented metamaterials are not bound by such constraints. These newly accessible electromagnetic properties make these materials an excellent platform for demonstrating unusual optical phenomena and unique applications such as subwavelength imaging and planar lens design. 'Negative-index materials', as first proposed, required the permittivity, epsilon, and permeability, mu, to be simultaneously less than zero, but such materials face limitations. Here, we demonstrate a comparatively low-loss, three-dimensional, all-semiconductor metamaterial that exhibits negative refraction for all incidence angles in the long-wave infrared region and requires only an anisotropic dielectric function with a single resonance. Using reflection and transmission measurements and a comprehensive model of the material, we demonstrate that our material exhibits negative refraction. This is furthermore confirmed through a straightforward beam optics experiment. This work will influence future metamaterial designs and their incorporation into optical semiconductor devices.
authors.affiliation: Department of Electrical Engineering, Princeton University, Princeton, NJ 08544, USA. ajhoffma@princeton.edu
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hoffman
authors.forename: Leonid
authors.initials: L
authors.lastname: Alekseyev
authors.forename: Scott S
authors.initials: SS
authors.lastname: Howard
authors.forename: Kale J
authors.initials: KJ
authors.lastname: Franz
authors.forename: Dan
authors.initials: D
authors.lastname: Wasserman
authors.forename: Viktor A
authors.initials: VA
authors.lastname: Podolskiy
authors.forename: Evgenii E
authors.initials: EE
authors.lastname: Narimanov
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Sivco
authors.forename: Claire
authors.initials: C
authors.lastname: Gmachl
mesh_terms: D003198:Computer Simulation; D004563:Electrochemistry / Q000379:methods*; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation; D012666:Semiconductors