Applied Physics

Negative Refraction Hits the Spot

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Science  09 Apr 2004:
Vol. 304, Issue 5668, pp. 173
DOI: 10.1126/science.304.5668.173d

Our familiarity with optical effects has generally been confined to materials with a positive index of refraction; i.e., lenses are curved, and imaging of an object is limited by the diffraction limit. A set of recently developed materials, or metamaterials, that can be designed with electrical and magnetic properties spanning the entire plane of positive and negative permeability (μ) and permittivity (ϵ) have been predicted to give rise to a number of somewhat counterintuitive optical effects.

Two groups present experimental data confirming some of these predictions using a flat slab of metamaterial designed to have a negative refractive index in the microwave regime. With μ= −1 and ϵ positive, Smith et al. demonstrate the ability to focus s-polarized light by a planar slab. With μ and ϵ both negative, Grbic and Eleftheriades demonstrate focusing by their planar slab of material, and moreover, that the image formed can beat the diffraction limit. By decreasing the length scales of these materials down to optical wavelengths, it should be expected that our field of familiarity with optics will become greatly expanded. — ISO

Appl. Phys. Lett. 84, 2244 (2004); Phys. Rev. Lett. 92, 117403 (2004).

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