封面文章

力學(xué)

來源出版物：SCIENCE CHINA Physics，Mechanics & Astronomy，2015，58（8）： 084201

聯(lián)系郵箱：HONG Ming-hui，elehmh@nus.edu.sg

封面介紹：Terahertz metamaterials offer an artificially means to engineer the electromagnetic interactions between terahertz wave and materials. The ability to effectively manipulate terahertz wave via metamaterials has led to various functional terahertz optical devices，such as polarizers，filters，modulators，switches，lenses and sensors. In the article，we experimentally investigated a gammadion metamaterial for terahertz wave amplitude modulation and broadband resonance tunability. Owning to the rotational symmetry of gammadion metamaterials，they can support different resonance modes. Previous works have reported multi-layer gammadion metamaterials with giant optical activities. We designed one layer of gammadion metamaterials with splits to investigate different resonance modes for terahertz wave manipulation. The designed splits enable excitation of different resonance modes for terahertz wave amplitude modulation. By changing the relative position of the splits，broadband static resonance tunability can be achieved. To extend the functionality of our design，we simulated the gammadion metamaterials when splits were covered with phase change materials for active terahertz modulation. The gammadion metamaterials embedded with splits，as a simple and compact design，can be applied to make efficient terahertz wave manipulation devices（See the article No. 084201 by WANG Da-cheng et al.）.

Selective excitation of resonances in gammadion metamaterials for terahertz wave manipulation

WANG Da-cheng，HUANG Qin，QIU Cheng-wei，et al.

A gammadion terahertz（THz）metamaterial embedded with a pair of splits is experimentally investigated. By introducing the pair of splits at different arms，the transmitted amplitude at the resonance frequency can be manipulated from 61% to 24%. Broadband static resonance tunability from 1.11 to 1.51 THz is also demonstrated via varying the relative split positions at certain arms. The amplitude change and static resonance tunability are attributed to the introduced split pairs，which enable selective excitation of different resonance modes in the gammadion metamaterials. This work promises a new approach to design THz functional devices.

terahertz； gammadion metamaterials； transmission