Repulsive Casimir force in chiral metamaterials

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TETY
Photonic- Phononic- and MetaMaterial Group Activities
Mainly theory, also experiment (characterization)
Main research topics
Metamaterials
Photonic crystals
Plasmonic structures
Web: http://esperia.iesl.forth.gr/~ppm
TETY
Main group members
Senior
C. M. Soukoulis (TETY/FORTH)
M. Kafesaki (FORTH/TETY)
E. N. Economou (FORTH)
N. Katsarakis (TEI/FORTH)
Th. Koschny (FORTH/ISU)
Post-docs
G. Kenanakis (exp)
N. H. Shen
R. S. Penciu
A. Reyes-Coronado
S. Foteinopoulou
PhD
T. Gundogdu (exp)
Students
N. Vasilantonakis (exp)
Ch. Mavidis
I. Tsiapa (exp)
Main collaborations
TETY
FORTH-IESL
G. Konstantinidis’ group - microfabrication
M. Farsari’s group - direct laser writing
S. Tzortzakis’ group - THz time domain spectroscopy
M. Wegener’s group @ Karlsruhe Institute of Technology,
Germany
E. Ozbay’s group @ Bilkent University, Turkey
J. Pendry’s group @ Imperial College, UK
V. Orera group @ Univ. of Zaragoza, Spain
Profactor company, Austria
….
Publications (2006-2010)
TETY
Publications number (with TETY affiliation): ~70
(3 Science, 4 PRL, 4 OL, 26 PRB, 7 APL, 11 OE)
Citation number for these publications: ~2000
TETY
Metamaterials
Artificial, structured (in subwavelength scale) materials
Electromagnetic (EM) properties
derive from shape and distribution
of constituent units (usually metallic
& dielectric components)
EM properties not-encountered in
natural materials
EM properties


Electrical
Magnetic
permittivity permeability
Possibility to engineer electromagnetic properties
TETY
Left-handed metamaterials
Negative electrical permittivity ()
Negative magnetic permeability ()
k

c
Sov. Phys. Usp. 10, 509 (1968)
 real
n    n   
2
Negative ε, μ, n
Novel and unique propagation
characteristics in those materials!
Novel phenomena in left-handed metamaterials
TETY
Backwards
propagation
(opposite phase
& energy
velocity)
S
S=E×H
Flat lenses “Perfect” lenses
(subwavelength
resolution)
air
LHM
air
Negative
refraction
AIR
θ1
LHM,
n2<0
θ2
source
• Zero-reflection possibility
• Opposite Doppler effect
• Opposite Cherenkov
radiation
• ……
•Interesting physical system
•New possibilities for light manipulation
 important potential applications
Application areas of left-handed metamaterials
TETY
New solutions and possibilities in
•Imaging/microscopy
•Lithography
•Data storage
Exploiting the
subwavelength resolution
capabilities of LHMs
•Communications and information processing
(subwavelength guides, optimized/miniaturized
antennas & filters, improved transmission lines ...)
•….
Metamaterials beyond negative index
TETY
High index metamaterials
Shrinkage of devices
Cloaking
Low index metamaterials
Parallel beam
formation
Indefinite media
Single-negative media
Hyperlensing
Bi-anisotropic media
Designing left-handed metamaterials
TETY
Most common approach: Merging structures of negative
permittivity (ε) with structures of negative permeability (μ)
Negative permeability:
Structures of resonant
loop-currents
Negative permittivity:
Continuous wires
E
C
L
j
Split Ring
Resonator
(SRR),
Pendry,
1999
Short-slabspair, Shalaev,
2002
m  1/ LC
Microwave (mm-scale) structures
TETY
Micro and nano-scale structures
TETY
Fabricated in MRG
1.4 μm
780 nm
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional isotropic left-handed
metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional isotropic left-handed
metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Optical metamaterials
THz and optical structures
TETY
Five layers !
Fabricated
in Crete
Silver in polyimide
Optics Letters 30, 1348 (2005)
5m
μ<0 @ ~6 THz
n<0 @ 1.4 μm
Re(n)=-0.6 @ 780 nm
Optical metamaterials
“Magnetic” metamaterials response in high frequencies
TETY
Al metal
Glass substrate
No negative permeability
at arbitrarily high
frequencies
Reducing a
Results not affected by
metal losses
a: u.c. size
• Saturation of response frequency in small length scales (a<500
nm)
•Vanishing of negative permeability band-width
•Weakening of permeability resonance
Optical metamaterials with gain
TETY
Gain atoms (4-level) embedded in host medium: In Finite Difference Time
Domain Method are driven oscillators which couple to the local E field
Rate equations:
N 3
N
 pump N 0  3
t
 32
N3
N2
N 2 N 3
1
P N 2


E

t
 32 a
t  21
pump
N1 N 2
1
P N1


E

t  21 a
t  10
N1
N 0 N1

 pump N 0
t
 10
N0
Driven oscillators:
 2P
P
2




P   a N E
a
2
t
t
σa is the coupling strength of P to the
external E field and ΔN=N2-N1
N3 /  32
Lasing ωa
1
P
E
a t
N2 /  21
N1 /  10
Same method
for
Maxwell’s
equations:
examining
E  P
B   H in
lasing
threshold
photonic




E  
0
t t
t
crystals (with
M. Farsari)
C. Soukoulis’ collaboration with Karlsruhe
and MRG
Phys. Rev. B: 79, 241104 (Rapid) (2009)
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional isotropic left-handed
metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
index behaviour (chiral or anisotropic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional isotropic left-handed
metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
index behaviour (chiral or anisotropic metamaterials)
• To explore novel phenomena and possibilities in
metamaterials
Switchable and tunable metamaterials
TETY
The principle:
Blue-shift tunable metamaterials
& Dual-band switches
PRB, 79, 161102 (R) (2009)
UV
Collaboration with S.
Tzortzakis’ group
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
New designs/approaches
Negative refractive index in chiral media
TETY
Chiral structure: not-identical to its mirror image
n    
•Different index for left- and righthanded circularly polarized waves
•Alternative path to achieve negative
index
Lefthanded
Righthanded
D   E  i H
B   H  i E
Besides negative index:
•Polarization rotation
•Circular dichroism
Negative index
Large polarization rotation
Large circular dichroism
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Novel phenomena and possibilities in metamaterials
TETY
•Super-lensing in anisotropic “negative”
metamaterials
•Electromagnetically-induced-transparency in
metamaterials
•Repulsive Casimir force in chiral metamaterials
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Besides metamaterials ?
Photonic crystals
Plasmonic systems
Lasing threshold for 2D inverse photonic crystals (TM)
TETY
Air
Gain
Thickness: 8400 nm
E
H
k
Lattice constant a = 840 nm
Width of square hole: w = 540 nm
Emission frequency: 100 THz
Dielectric constant of gain: 11.7
Much lower lasing threshold (at
upper band edge) than bulk gain
Main investigation aims/directions
TETY
• Analyze, understand, optimize and tailor metamaterial
response
• Achieve optical metamaterials – reduce losses in
metamaterials
• Achieve three-dimensional metamaterials
• Create switchable and tunable metamaterials
• Devise/analyze new designs and approaches for negative
refraction and other interesting effects (chiral, anisotropic,
polaritonic metamaterials)
• Explore novel phenomena and possibilities in
metamaterials
Besides metamaterials ?
Photonic crystals
Plasmonic systems
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