Physics, Mechanics & Astronomy

© Science China Press and Springer-Verlag Berlin Heidelberg 2015 phys.scichina.com link.springer.com
*Corresponding author (email: elehmh@nus.edu.sg)
†Contributed by HONG MingHui (Associate Editor)
• Article • August 2015 Vol. 58 No. 8: 084201
doi: 10.1007/s11433-015-5674-7
Selective excitation of resonances in gammadion metamaterials for
terahertz wave manipulation†
WANG DaCheng, HUANG Qin, QIU ChengWei & HONG MingHui*
Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117581, Singapore
Received February 6, 2015; accepted March 12, 2015
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
PACS number(s): 07.57.Pt, 42.25.Bs, 41.20.Jb, 78.20.Ci
Citation: Wang D C, Huang Q, Qiu C W, et al. Selective excitation of resonances in gammadion metamaterials for terahertz wave manipulation. Sci China-
Phys Mech Astron, 2015, 58: 084201, doi: 10.1007/s11433-015-5674-7
1 Introduction
THz technology, a cutting edge research field, promises a
family of wonderful applications, ranging from scanners in
airport security, non-destructive inspection and quality control
to bio-imaging, bio-sensing, high speed communication
and astronomy [1]. All these intriguing applications are
based on the unique properties of THz wave, which sits
between microwaves and infrared radiation. For instance,
THz wave can pass through many dielectric and semiconductor
materials, but shows unique fingerprints when interacting
with bio-molecules. Meanwhile, THz wave is a
non-ionizing radiation, which is harmless to tissues for biological
applications [2]. However, the interactions between
THz wave and natural materials are weak, which limits the
effective manipulation of THz wave. One of the promising
approaches to push THz optics into real world applications
is to manipulate THz wave based on artificial materials. In
visible, infrared and microwave ranges, artificially designed
materials have shown their uniqueness for novel optical
properties, such as negative index [3], cloaking [4], extremely
short wavelength [5–12] and strong dispersion
[13–17]. These properties have led to revolutions in the entire
field of subwavelength optics. Based on the extremely
short wavelength of the collective excitation of electrons in
metallic surfaces, Luo’s group theoretically and experimentally
demonstrated the deep-subwavelength interference
effect in 2004 [5,7], which was further utilized to break
Abbe’s diffraction limit and achieve high-resolution optical
imaging and lithography [8]. In 2005, Fang et al. [9]
demonstrated that this sub-diffraction phenomenon was a
direct consequence of the superlens effect. The extremely
short wavelength of surface wave can also be utilized to
modify traditional law of reflection and refraction [10].
Based on the revised law, a series of flat plasmonic devices
were elaborately designed to realize functionalities such as
abnormal beam deflection, subwavelength focusing and