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Published online: 21 January 2009 | doi:10.1038/nchina.2009.12

Metamaterials: Stop light!

Tim Reid

Introduction

© (2009) OSA

The fields of optical communication and quantum computing could greatly benefit from devices that can stop or delay the passage of light. Yijun Feng and co-workers at Nanjing University¹ have designed a very promising waveguide that could stop light inside an air channel in a man-made metamaterial.

Metamaterials, which have special optical properties such as a negative refractive index, have previously been proposed for slowing down different frequencies of light by varying amounts to produce a 'trapped rainbow'. However, this would require 'isotropic' metamaterials with uniform properties in all directions, which are very difficult to make.

Feng and co-workers propose making use of anisotropic metamaterials. These can be practically imitated by alternating materials such as silicon dioxide and silver in layers much thinner than the wavelength of the incoming light.

The researchers have also redesigned the waveguide so that instead of passing through the metamaterial itself, light is guided through an air channel and therefore loses less power. If the air channel is made to taper (see image), the front of a light pulse should travel slower than the rear, causing compression of the pulse. At a certain critical point, the forward and backward modes will degenerate together, stopping the wave.

The authors of this work are from:
Key Laboratory of Modern Acoustics, Ministry of Education, and Department of Electronic Science and Engineering, Nanjing University, Nanjing, China.

Reference

1. Jiang, T., Zhao, J. & Feng, Y. Stopping light by an air waveguide with anisotropic metamaterial cladding. Opt. Express 17, 170–177 (2009).  | Article | PubMed |