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10-05/06 :: May/June 2010

nanotimes News in Brief

59

Image: An omnidirectional electromagnetic absorber made of metamaterials, © State Key Laboratory of Millimeter Waves, Department of Radio Engineering, Southeast University, Nanjing, China

Chinese researchers have successfully built an electromagnetic absorbing device for microwave frequencies. The device, made of a thin cylinder comprising 60 concentric rings of metamaterials, is capable of absorbing microwave radiation, and has been compared to an astrophysical black hole (which, in space, soaks up matter and light). The research shows how the researchers utilised the special properties of metamaterials, a class of or- dered composites which can distort light and other waves.

Qiang Cheng and Tie Jun Cui of the State Key La- boratory of Millimeter Waves at Southeast Uni- versity in Nanjing, China, designed and fabricated their absorbing device, officially called an “omnidi- rectional electromagnetic absorber”, using 60 strips of circuit board arranged in concentric layers coated in copper. Each layer is imprinted with alternating patterns, which resonate or don’t resonate in elec- tromagnetic waves. The designed device can trap and absorb electro- magnetic waves coming from all directions by spira-

ling the radiation inwards and converting its energy into heat with an absorption rate of 99%. Hence it behaves like an “electromagnetic black body” or an “electromagnetic black hole”.

At the moment, the device only works with micro- waves, but the researchers are planning to develop a black hole for visible light next. Qiang Cheng, Tie Jun Cui, Wei Xiang Jiang and Ben Geng Cai: An omnidirectional electromagnetic absor- ber made of metamaterials, In: New Journal of Physics, Volume 12(2010), Issue 6, June 2010, Article 063006, DOI:10.1088/1367-2630/12/6/063006: http://dx.doi.org/10.1088/1367-2630/12/6/063006

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