MetamaterialsKhalid Saeed Lateef Al Badri

T.CSÜLEMAN DEMİREL UNIVERSITY

FEN BİLİMLERİ ENSTİTÜSÜMühendislik fakültesi

ELEKTRONİK VE HABERLEŞME MÜHENDİSLİĞİ

Negative refractive index: A historical review

L.I. Mandelshtam described negative refraction and backward propagation of waves in his textbook published in 1944.[7]

Left handed materials , characterized by negative effective value of refractive index. These materials were theoretically predicted in 1967 by Veselago [7]

Pendry group, In 1999, they open the door to design Metamaterial by there design array of split ring resonator and mesh wire.

Materials & MetamaterialsThe electromagnetic response of a material is defined by its electromagnetic properties: permittivity and permeability

Metamaterials

• Metamaterial is an arrangement of artificial structural elements, designed to achieve advantageous and unusual electromagnetic properties• meta = beyond (Greek)

Metamaterials

Normal water = 1.7, = 1

NIM water* = -1.3, = -1.3

*Gunnar Dolling, et. al., Opt. Exp.14, 1842 (2006)Perfect Lens (Pendry, 2000)

Light deflection

n > 0

n < 0

Light focusing

Metamaterials: artificially engineered materials possessing electro-magnetic properties that do not exist in naturally occurring materials.

Names and terminologies•Left-hand media•Media with negative refraction index•Backward-wave media•Double-negative (DNG) metamaterials

Backward Propagation

Snell’s Law

Negative refractive index

In naturally exiting substances permittivity and permiability are positve (except the cases of noble metals like gold silver etc where permitivitty is negative for certain range of frequency).

0

0

Now lets consider that :

( )( )effn n

Negative refractive index

• So we see that a negative refractive index can be obtained in principle if both permittivity and permeability are negative simultaneously.• This makes the left hand material.•Why we want negative refractive index ??

Cloaking

Different structures used for designing NIM.

• The famous SRR(split ring resonator suggested by Sir Pendry)• First Realized by D.R

Smith group in 2001.

designing NIM. • Motivation: metallic

behavior at GHz frequencies• Problem: the

dielectric response is negatively (close to) infinite• Solution: “dilute” the

metal

2

2

a

rnn eneff

m

enep

0

22

eff

effeffp m

en

0

22,

Designing NIM 1D and 2D systems

• Periodicity or inclusions much smaller than wavelength • 2+1D or 1+2D (dimensions of

variations)• Effective dielectric response

determined by filling fraction f

Nanowire metal-dielectric metamaterial

λa

Double Negative Media