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()+i2() and complex magnetic permeability() = 1()+i2(). 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.

------

PRIMARY TOPIC:A5

SECONDARY TOPIC:U

THIRD TOPIC:T

PREFERRED FORMAT OF PRESENTATION (ORAL/POSTER): O

------

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