Transcript Repulsive Casimir force in chiral metamaterials
TETY
Photonic- Phononic- and Meta Material
Group Activities
Mainly theory, also experiment (characterization)
Main research topics Metamaterials Photonic crystals Plasmonic structures
Web: http://esperia.iesl.forth.gr/~ppm
Main group members
TETY
Senior C. M. Soukoulis (TETY/FORTH) M. Kafesaki (FORTH/TETY) E. N. Economou (FORTH) N. Katsarakis (TEI/FORTH) Th. Koschny (FORTH/ISU) PhD T. Gundogdu (exp) Post-docs G. Kenanakis (exp) N. H. Shen R. S. Penciu A. Reyes-Coronado S. Foteinopoulou 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
Metamaterials
TETY
Artificial, structured (in sub wavelength 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 permittivity
Magnetic permeability Possibility to engineer electromagnetic properties
TETY
Left-handed metamaterials
Negative electrical permittivity (
) Negative magnetic permeability (
) Sov. Phys. Usp. 10, 509 (1968
)
k
c
real
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) Flat lenses “Perfect” lenses (subwavelength resolution ) air LHM S Negative refraction AIR LHM, n 2 <0 air S=E×H θ 1 source θ 2
• • •
Zero-reflection possibility Opposite Doppler effect Opposite Cherenkov
•
radiation ……
•
Interesting physical system
•
New possibilities for light manipulation
important potential applications
TETY
Application areas of left-handed metamaterials New solutions and possibilities in
• •
Imaging/microscopy Lithography Exploiting the subwavelength resolution capabilities of LHMs
•
Data storage
•
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
C L
j Split Ring Resonator (SRR), Pendry, 1999 E Short-slabs pair, Shalaev, 2002
m
1/
LC
TETY
Microwave (mm-scale) structures
TETY
Micro and nano-scale structures
Fabricated in MRG 1.4 μm 780 nm
Main investigation aims/directions
TETY
• • • • • •
A nalyze , 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
TETY
THz and optical structures
5
m Five layers !
Fabricated in Crete Silver in polyimide Optics Letters 30, 1348 (2005) 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
t
N
2
t
N
1
t
pump
N
0
N
3 32 1
N
3 32
E
P
t a
N
2 21 1
a
E
P
t
N
2 21
N
1 10
N
0
t
N
1 10 pump
N
0
Driven oscillators:
2
P
t
2
P
t
a
2
P
a
N
E σ a is the coupling strength of P to the external E field and ΔN=N 2 -N 1
N 3 N 2 pump N 1 N 0
E
crystals
B
N 3 / 32 1 Lasing ω a
E
P
a
t
N 2 / 21 N 1 / 10
H
0
E
P 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
TETY
Switchable and tunable metamaterials
UV The principle: Blue-shift tunable metamaterials & Dual-band switches Collaboration with S. Tzortzakis’ group PRB, 79, 161102 (R) (2009)
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 right handed circularly polarized waves
•
Alternative path to achieve negative index
Left handed Right handed
D B
E
H
i
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
TETY
Novel phenomena and possibilities in metamaterials
•
Super-lensing in anisotropic “negative” metamaterials
•
Electromagnetically-induced-transparency in metamaterials
•
Repulsive Casimir force in chiral metamaterials
Main investigation aims/directions
TETY
• • • • • •
A nalyze , 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 Photonic crystals Besides metamaterials ?
Plasmonic systems
Air
TETY
Lasing threshold for 2D inverse photonic crystals (TM)
Gain Thickness: 8400 nm E H k Lattice constant a = 840 nm
Much lower lasing threshold (at
Width of square hole: w = 540 nm Emission frequency: 100 THz
upper band edge) than bulk gain
Dielectric constant of gain: 11.7
Main investigation aims/directions
TETY
• • • • • •
A nalyze , 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 Photonic crystals Besides metamaterials ?
Plasmonic systems