title: Self-collimation of light over millimeter-scale distance in a quasi-zero-average-index metamaterial.
abstract: Inspired by the concept of complementary media, we experimentally demonstrate that an engineered metamaterial made of alternating, stripe layers of negatively refracting (photonic crystals) and positively refracting (air) materials strongly collimates a beam of near-infrared light. This quasi-zero-average-index metamaterial fully preserves the beam spot size throughout the sample for a light beam traveling through the metamaterial a distance of 2 mm-more than 1000 times the input wavelength lambda=1.55 microm. These results demonstrate the first explicit experimental verification of optical antimatter as proposed by Pendry and Ramakrishna [J. Pendry and S. Ramakrishna, J. Phys. Condens. Matter 15, 6345 (2003)10.1088/0953-8984/15/37/004], using two complementary media in which each n(eff)=-1 layer appears to annihilate an equal thickness layer of air.
authors.affiliation: CNR-IMM, Unità di Napoli, Via P. Castellino 111, 80131 Napoli, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Mocella
authors.forename: S
authors.initials: S
authors.lastname: Cabrini
authors.forename: A S P
authors.initials: AS
authors.lastname: Chang
authors.forename: P
authors.initials: P
authors.lastname: Dardano
authors.forename: L
authors.initials: L
authors.lastname: Moretti
authors.forename: I
authors.initials: I
authors.lastname: Rendina
authors.forename: D
authors.initials: D
authors.lastname: Olynick
authors.forename: B
authors.initials: B
authors.lastname: Harteneck
authors.forename: S
authors.initials: S
authors.lastname: Dhuey