Optics & Photonics News

Volume 15 Page 33-7


Manipulating the Near Field with Metamaterials

JB Pendry


Light creates images with a pencil no sharper than the wavelength and hence the limitations in performance of DVDs, of optical lithography and a host of other imaging technologies. Or so we are led to believe. Yet there are circumstances where electromagnetic fields define detailed structure on a much finer scale. Consider two very small and closely spaced dielectric spheres illuminated by visible light. Probing the electric dipole field around the spheres would clearly reveal the position of the spheres even if they were each only a nanometer in diameter and separated by as little as ten nanometers. Only when we try to capture and focus the scattered light do we lose the fine details. This example shows that there are two sorts of light: the far field which radiates freely and can be captured by a lens, and the near field which does not radiate freely but contains the finest details of an object. Nor is the near field some rare and exotic quantity, rather it is to be found whenever light is radiated or scattered. In fact it is the dominant component of the fields close to an aerial, and as such can be something of an obstacle to efficient radiation from mobile telephones.


This paper is available as a PDF file.

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