Abstract
Metamaterials offer unprecedented flexibility for manipulating the optical properties of matter, including the ability to access negative index, ultrahigh index and chiral optical properties. Recently, metamaterials with near-zero refractive index have attracted much attention. Light inside such materials experiences no spatial phase change and extremely large phase velocity, properties that can be applied for realizing directional emission, tunnelling waveguides, large-area single-mode devices and electromagnetic cloaks. However, at optical frequencies, the previously demonstrated zero- or negative-refractive-index metamaterials have required the use of metallic inclusions, leading to large ohmic loss, a serious impediment to device applications. Here, we experimentally demonstrate an impedance-matched zero-index metamaterial at optical frequencies based on purely dielectric constituents. Formed from stacked silicon-rod unit cells, the metamaterial has a nearly isotropic low-index response for transverse-magnetic polarized light, leading to angular selectivity of transmission and directive emission from quantum dots placed within the material.
Original language | English |
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Pages (from-to) | 791-795 |
Number of pages | 5 |
Journal | Nature Photonics |
Volume | 7 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2013 |
Funding
This work was funded by the Office of Naval Research (programmes N00014-11-1-0521 and N00014-12-1-0571) and the United States–Israel Binational Science Foundation (programme 2010460). A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is sponsored at Oak Ridge National Laboratory by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. The authors thank N. Lavrik for discussions regarding RIE processing.