ppt t thongrattanasiri_metamaterials_g-ene
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Graphene Plasmonics
Sukosin Thongrattanasiri,*
Frank Koppens,# Darrick Chang,$ and Javier Garca de Abajo*,&
*CISC, Madrid#ICFO, Barcelona
$
Caltech, Pasadena&On sabbatical at ORC, Southampton, 2010-2011
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Milestones in Plasmonics
Graphene Plasmonics Metamaterials, October 2011
Experimentally evidence
but not unexplained until 1957 (Ritchie, theory)and 1959 (Powell and Swan, experiment)
Metal plasmons, 1950s
Jablan et al., Phys. Rev. B 80, 245435 (2009)Velizhanin and Efimov, Phys. Rev. B 84, 085401 (2011)Vakil and Engheta, Science 332, 1291 (2011)Chen and Alu, ACS Nano 5, 5855 (2011)Koppens et al., Nano Lett. 11, 3370 (2011)Nikitin et al., arXiv:1104.3558v1 (2011)Sukosin et al., arXiv:1106.4460v1 (2011)
Ju et al., Nature Nanotech. 6, 630 (2011)
Increasing interest from theory
and experimental proof
Graphene plasmons, 2009-2011
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Outline
Graphene Plasmonics Metamaterials, October 2011
plasmonic background
graphene background
graphene plasmonics 100% light absorption
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Plasmons
Graphene Plasmonics
plasmons quantum of rapid oscillations of conduction-electrons
surface plasmon - Wikipedia
localized plasmon
Myroshnychenko et al., Chem. Soc. Rev. 37, 1792 (2008)
Metamaterials, October 2011
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Graphene
Graphene Plasmonics
Das Sarma et al., Rev. Mod. Phys. 83, 407 (2011)
a flat monolayer of carbon atoms tightly packed into a 2-dimensionalhoneycomb lattice
Physics World, Nov 2006
= 3 +
Expandingk=K
+q
close toK
(K
) with |q
|
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Unique Properties
Graphene Plasmonics
electrons and holes near Dirac points behave as particles describedby the Dirac equation for -spin particles massless Dirac fermions
vF=106 m/s, similar to noble metals
minimum conductivity at T=0K:
,
,
impurity concentration, rippling, interaction with substrate
high electron mobility at room temperature
large mean free path (up to several microns) extremely good conductor
Crystal mobility (cm2/Vs)
graphene 10,000-200,0001
GaAs 8,0002
GaSb 5,0002
diamond 1,8002
1Geim et al., Nat. Mat. 6, 183 (2007)2Kittel, Introduction to Solid State Physics, 8th ed
Metamaterials, October 2011
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Unique Properties (cont.)
Graphene Plasmonics
high 3D plasmon-confinement: ~106 times smaller thandiffraction limit
tunable material absorption = 2.3% over a broad spectral range
Metamaterials, October 2011
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Optical Response
Graphene Plasmonics
real
imaginary
Falkovsky et al., Eur. Phys. J. B 56, 281 (2007)
Koppens et al., Nano Lett. 11, 3370 (2011)
Metamaterials, October 2011
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Plasmons in a Graphene Sheet
Graphene Plasmonics
Jablan et al., PRB 80, 245435 (2009)
For ,
+
Koppens et al., Nano Lett. 11, 3370 (2011)
Metamaterials, October 2011
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Graphene vs Gold
1
2
4
|
WZS
Z
V
i
iLp12
2
|
WZS
V
i
iEe F
!
1 monolayer of gold
(L=0.24 nm)graphene
(L=0.33 nm)
L
i
Z
VS
ZH
4|L
Graphene Plasmonics Metamaterials, October 2011
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Nanostructured graphene
Graphene Plasmonics
So far graphene, an extended sheet allows
high field confinement
long plasmon propagation (many plasmon wavelength)
But we can gain further benefits by nanostructuring extremely high field confinement
high plasmon localization
engineering plasmon resonances
Metamaterials, October 2011
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1D Plasmon Confinement: Nanoribbons
Graphene Plasmonics Metamaterials, October 2011
Koppens et al., Nano Lett. 11, 3370 (2011)
Width (nm)
Photon
energy(eV)
10.5 0.750.250.01
Extinction V/area
EF=0.2 eVlightE
ext
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0D Plasmon Confinement: Nanodisks
Graphene Plasmonics
=
Im
Sukosin et al., arXiv:1106.4460v1
Metamaterials, October 2011
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Experimental Proof of Nanoribbon Plasmons
Graphene Plasmonics Metamaterials, October 2011
Ju et al., Nature Nanotech. 6, 630 (2011)
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Light Absorption in Graphene
Graphene Plasmonics Metamaterials, October 2011
At plasmon resonance, an arrayofpatternedgraphene catches the light.
Higher absorption!!
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Absorption by a Thin Layer
Graphene Plasmonics
SymmetricEnvironment
A thin layer patterned with a period smaller than the wavelength canonly produce specularly reflected and transmitted beams (no diffraction).
= 1
= 1 1
= 50%
Full Detail: Sukosin et al., arXiv:1106.4460v1
Metamaterials, October 2011
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Absorption by a Thin Layer
Graphene Plasmonics
AsymmetricEnvironment
Full Detail: Sukosin et al., arXiv:1106.4460v1
, =1
1 + Re
, = 1 Re
Re + /
=1
cos
sin
Metamaterials, October 2011
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Array of Graphene Nanodisks
Graphene Plasmonics
1Garca de Abajo et al., PRB 65, 115418 (2002)2Stefanou et al., Comput. Phys. Commun. 113, 49 (1998)
3Garca de Abajo et al., Rev. Mod. Phys. 79, 1267 (2007)
Full Detail: Sukosin et al., arXiv:1106.4460v1
Numerical1. BEM1 multipolar scattering matrix
of each graphene nanodisk2. multiple-scattering method2 periodic structure
Analytical dipole model3
=
1/
5.52
+
2
3
;
=2
cos
=
2 cos
Metamaterials, October 2011
T l Li h Ab i
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Total Light Absorption
Graphene Plasmonics
Full Detail: Sukosin et al., arXiv:1106.4460v1
Metamaterials, October 2011
T t l Li ht Ab ti O idi ti lit
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Total Light Absorption: Omnidirectionality
Graphene Plasmonics
Full Detail: Sukosin et al., arXiv:1106.4460v1
Metamaterials, October 2011
C l i
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Conclusion
Funding:
Koppens et al., Nano Lett. 11, 3370 (2011)
Sukosin et al., arXiv:1106.4460v1 (2011)
graphene nanostructure
high field confinement
high plasmon localization
engineering plasmon resonance
omnidirectional total light absorption within an
atomically thick layer
strong light-matter interaction
a new direction in plasmonics metamaterials
more info on graphene plasmonics:
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