ELECTROMAGNETISM DE TIP LEFT- HANDED INTR-O STRUCTURA METALO-DIELECTRICA.

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ELECTROMAGNETISM DE TIP LEFT- HANDED INTR-O STRUCTURA METALO-DIELECTRICA. Cristian Kusko si Mihai Kusko IMT-Bucharest, Romania E-mail: [email protected]

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ELECTROMAGNETISM DE TIP LEFT- HANDED INTR-O STRUCTURA METALO-DIELECTRICA. Cristian Kusko si Mihai Kusko IMT-Bucharest, Romania E-mail: [email protected]. Electromagnetism de tip LH. Structura periodica de rezonatori magnetici si/sau electrici - PowerPoint PPT Presentation

Transcript of ELECTROMAGNETISM DE TIP LEFT- HANDED INTR-O STRUCTURA METALO-DIELECTRICA.

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ELECTROMAGNETISM DE TIP LEFT- HANDED INTR-O STRUCTURA

METALO-DIELECTRICA.

Cristian Kusko si Mihai Kusko

IMT-Bucharest, Romania

E-mail: [email protected]

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Electromagnetism de tip LH

• Structura periodica de rezonatori magnetici si/sau electrici• Lungimea de unda a campului EM trebuie sa fie mult mai mare

decat dimensiunile fiecarei componente individuale• Sistem “omogen”• Proprietati magnetice si electrice artificiale• Retea rectangulara de fire metalice subtiri - Comportament tip

Drude

Permitivitate negativa J. B. Pendry, A. J. Holden, W. J. Stewart, and I. Youngs, Phys. Rev. Lett., 76, pp. 4773, (1996)

• Retea rectangulara de rezonatori “split-ring”

Permeabilitate negativaJ.B. Pendry, A.J. Holden, D.J. Robbins, and W.J. Stewart, IEEE transactions on microwave theory and techniques, 47, (1999)

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Metamaterial Magnetic - configuratie SRR

Polarizare TM Curenti EddyMoment magnetic indusResonantaRaspuns magnetic Moment magnetic pozitiv sau negativ

>>aAproximatia mediului efectivPermeabilitate negativa

µ<0

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Celula unitate a ubui cristal fotonic 2-dimensional continind un clindru cu permitivitatea εcyl Sistemul prezinta o permeabilitatemagnetica efectiva µy.

Celula unitate a unei structurimetalo-dielectrice continind un cristal fotonic dielectric orientat in directia y intretesut cu o retea de fire metalice orientate in directia x

Sistemul prezinta constantele efective µy and εx

LHM unidirectional

n<0

µ<0µ<0

<0

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Resonante Mie in SrTiO3 la frecvente de microunde

Z. Zhai, C. Kusko, N. Hakim, S. Sridhar, A. Viektine, and A. RevcolevskiRev. Sci. Instr. 70, 3151 (2000)L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media

t

D

yH

2

aka

Zero al functiei Bessel

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3.4 3.6 3.8 4.0 4.2 4.40.0

0.2

0.4

0.6

0.8

1.0

Po

we

r

f(GHz)

reflection transmission

Puterea reflectata (linia neagra) si puterea transmisa (linia gri) a cristalului fotonic dielectricband gap datorat zero order Mie resonance,

Raspunsul EM a unui cristal fotonic cu constanta dielectrica

S. O’Brien and J. B. Pendry, J. Phys. Condensed Matter, 14 6383, (2002).

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4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.00.0

0.2

0.4

0.6

0.8

1.0

Pow

er

f(GHz)

reflection transmission

Puterea reflectata (linia neagra) si puterea transmisa (linia gri) a cristalului fotonic metalic

)(1)(

2

iP

R

dd

cP

ln

2

2

22

Cristal Fotonic metalic

Drude

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3.7 3.8 3.9 4.0 4.1 4.2 4.30.0

0.2

0.4

0.6

0.8

1.0

Pow

er

f(GHz)

reflection transmission

Raspunsul EM al structurii metalo-dielectrice

Puterea reflectata (linia neagra) si puterea transmisa (linia gri) a structurii LHM metalo-dielectrice

Filtru Pass-band

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Faza undei propagate

High dielectric PC

LHM structure

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Doua celule unitate a configuratiei de “single split rezonator” metalici de forma cilindrica reprezentati de-a lungul directiei x de propagare a campului electromagnetic. Componenta magnetica a campului este paralela cu generatoare cilindrilor.

A. Ishikawa, T. Tanaka and S. Kawata, Phys. Rev. Lett. 95, 237401 (2005)

R=125 nma=625nmw=125 nm

g=18 nm

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Amplitudinea (linia rosie) si faza (linia albastra) a campului electromagnetic, obtinut prin simulare FDTD, intr-o structura SSRR de-a lungul directiei de propagare.

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Spectrul puterii reflectate a nanostructurii

SSRR ca functie de lungimea de unda (masurata in microni) a radiatiei incidente

0

0.10.2

0.30.4

0.50.6

0.70.8

0.9

3 3.5 4 4.5 5 5.5 6

r

0

0.5

1

1.5

2

2.5

3

3.5

3 3.5 4 4.5 5 5.5 6

phase

Variatia schimbarii de faza la reflexie ca functie de lungimea de unda a radiatiei incidente.

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Dependenta de lungimea de unda a indicelui de refractie complex

0

0.5

1

1.5

2

2.5

3 3.5 4 4.5 5 5.5 6

Im_n

Re_n

00.5

11.5

22.5

33.5

44.5

3 3.5 4 4.5 5 5.5 6

Im_Z

Re_Z

Dependenta de lungimea de unda a impedantei de suprafata complexa

*

*

1

1

r

rZ

Z

neff Zneff

S. O’Brien and J. B. Pendry, J. Phys. Condensed Matter, 14 6383, (2002).

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Dependenta de lungimea de unda a partilor reale pentru permeabilitatea magnetica (linia albastra) si permitivitatea electrica (linia galbena). In domeniul spectral 6 – 7.2 centimetri permeabilitatea sistemului este negativa.

-8

-6

-4

-2

0

2

4

6

3 3.5 4 4.5 5 5.5 6

Re_mu

Re_eps

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Concluzii

• Propagare LH intr-o structura metalo-dielectrica• Microunde• Infrarosu sau vizibil?

• Determinarea structurii de benzi• Calculul permitivitatii si permeabilitatii