INVITED
Narrow-Band Perfect Metamaterial Based Absorber for TerahertzImaging
W.J. Padilla1,N. Landy1, C. Bingham1,H. Tao2,
R.D.Averitt3, X. Zhang2
1BostonCollege, Department of Physics, 140 Commonwealth
Ave., Chestnut Hill, MA 02467, USA.
2BostonUniversity, Department of Manufacturing Engineering,
15 Saint Mary's Street,Brookline, Massachusetts02446, USA.
3BostonUniversity, Department of Physics, 590 Commonwealth
Avenue, Boston,Massachusetts02215, USA.
Corresponding author email:
Recently, there has been considerable effort to construct engineered electromagnetic materialsfor operation specifically within the terahertz gap[1,2]. Artificial systems, called metamaterials, are composites whose EM propertiesoriginate from oscillating electrons in unit cells comprised of highly conductive andshaped metals such as gold or copper. The sub-wavelength unit cell is replicated to form amaterial, which allows for a designed resonant response of the metamaterial's electrical andmagnetic properties. Metamaterials can be regarded as effective media and characterized bya complex electric permittivity () = 1()+i2() and complex magnetic permeability() = 1()+i2(). For many other applications it would be desirable to maximize theloss which is an aspect of metamaterial research that, to date, has received very little attention.A recent example is the creation of a resonant high absorber which has been demonstrated atmicrowave frequencies [3]. Such an absorber would be of particular importance at terahertzfrequencies where it is difficult to find naturally occurring materials with strong absorptioncoefficients that are also compatible with standard microfabrication techniques. By fabricatingbilayer metamaterial structures it becomes possible to simultaneously tune () and () suchthat a high absorptivity can be achieved. In principle, this tunability could lead to near unityabsorptivity. In practice this is limited by achievable fabrication tolerances.
We present an absorbing metamaterial element with near unity absorbance. Ourstructure consists of two metamaterial resonators that couple separately to electric and magnetic fields so as to absorb all incident radiation within a single unit cell layer.Unlike conventional absorbers, our metamaterial consistssolely of metallic elements. The underlying substrate can therefore be chosen independently of thesubstrate's absorptive qualities and optimized for other parameters of interest.Anexperimental absorptivity of 70% at 1.3 terahertz is demonstrated. Weutilize only a single unit cell in the propagation direction, thus achieving anabsorption coefficient = 2000 cm-1. These metamaterials are promisingcandidates as absorbing elements for thermally based THz imaging, due totheir relatively low volume, low density, and narrow band response.
[1]T. J. Yen, W. J. Padilla, N. Fang, D. C. Vier, D. R. Smith, J. B. Pendry, D. N. Basov and X. Zhang, Science 303, 1494 (2004).
[2]W. J. Padilla, M. T. Aronsson, C. Highstrete, M. Lee, A. J. Taylor and R. D. Averitt, Physical Review B 75, 041102R (2007).
[3]N. I. Landy, S. Sajuyigbe, J. J. Mock, D. R. Smith and W. J. Padilla, Submittedto Physical Review Letters.
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PRIMARY TOPIC:A5
SECONDARY TOPIC:U
THIRD TOPIC:T
PREFERRED FORMAT OF PRESENTATION (ORAL/POSTER): O
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Corresponding author name: Willie J. Padilla
Corresponding author email:
TOPICS
Please choose primary and secondary topics
AOptical properties of materials
A1General
A2Crystals
A3Polycrystalline bulk and film
A4Amorphous and organics
A5Nanostructures, including photonic crystals
BPreparation and Characterization of Quantum Dots, Quantum Wires and Other Quantum Structures
CExcitonic Processes
DLuminescence, Phosphors, Scintillators and Applications
EPhotoinduced Effects and Applications
FPhotoconductivity and Photogeneration
GNonlinear Optical Effects and Applications
HElectro-Optic Effects and Applications
IGlasses for Optics, Optoelectronics and Photonics (including ZBLAN, fluozirconate, oxyfluoride and other glasses)
JPolymers for Optics, Optoelectronics and Photonics
KSemiconductors for Optoelectronics
J1Semiconductors for Optoelectronics: Wide Bandgap
J2Semiconductors for Optoelectronics: Narrow Bandgap
J3Semiconductors for Optoelectronics: Heterostructures
LLight Emitting Devices (including organics)
MPhotonic and Optoelectronic Materials and Devices (including devices for telecommunications, laser and detectors)
NOptical Storage
OPhotovoltaics (materials and devices, and their properties)
PWaveguides and Integrated Photonics
QSilicon Photonics
ROptical Fibers and Fiber Sensors
SExperimental Techniques
TFemtosecond Spectroscopy
UTeraherz (THz) techniques, including materials, emitters and detectors
VDefect Spectroscopy
WPlasmons and Surface Plasmons
XSelected Topics (e.g. Photocatalysts in Materials, Materials for Energy Conversion etc)
Abstract submission
Deadline: 31 March, 2008
Note: Late abstracts may be considered at the discretion of the conference organizers.
Abstract acceptance: 15 April2008 (Tentative)
Manuscripts: To be submitted either before or during the conference using the instructions on the conference website