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Experiments on Superconducting Metamaterial-Induced Transparency Cihan Kurter, John Abrahams, Chris Bennett, Tian Lan, Steven M. Anlage,
L. Zhang, T. Koschny, C. Soukoulis (Ames/Iowa State)Alexander Zhuravel (Kharkov, Ukraine),
Alexey Ustinov (KIT, Karlsruhe, Germany),
Work Funded by NSF and ONR
Metamaterials 2010, Karlsruhe, Germany14 September, 2010
2
Metamaterial-Induced Transparency
Inspired by:Electromagnetically-Induced Transparency (EIT)
Light can be slowed, or even stopped at the EIT frequencyL. V. Hau, Nature (1999)Fleischhauer, PRL (2000)
N. Papasimakis, et al.Optics and PhotonicsNews, Oct. 2009Classical Analog of EIT
Garrido Alzar, et al.,Am J Phys (2002)
Strong dispersionwith little loss
12Dissipation 2 << 1
to coherently driveparticle 1
Atom
Probe FieldPump Field
Probe Frequency Probe Frequency
Pro
be
Ab
sorp
tion
3
Re[
x 1(t)
]
Atom
Probe Field
Pump Field
The “atom” has zero displacement at the EIT frequency, but largedisplacement for small de-tuning
12
2 << 1
1 = 4.0 x 10-2
2 = 1.0 x 10-7
Classical Analog of EITThe Importance of Strong Loss Contrast
Ab
sorb
ed P
ower
0 .98 0 .99 1 .00 1 .01 1 .020
50
10 0
15 0
Frequency
Ab
sorp
tion
2 = 1 x 10-7
2 = 1 x 10-3
2 = 1 x 10-2
1 = 4 x 10-2
4
l1
w1
g
l2
l3
w2
s1s2
ax
ay
Metamaterial-Induced TransparencyWork with L. Zhang, T. Koschny, and C. Soukoulis (Iowa State Univ.)
Cu (radiative)Normal metal
Nb (dark)Superconducting
X-band waveguide
Normal metal metamaterials:Papasimakis, PRL 2008Tassin, PRL 2009
Superconducting MetamaterialsMIT @ 10 GHz
E
B
Cu NbNb
12
5
Simulation ResultsMetamaterial-Induced Transparency
9 10 11 12
0.01
1
0.1
Frequency (GHz)
T,R
TR
Inde
x of
Ref
ract
ion
Tra
nsm
issi
on a
nd
Ref
lect
ion
EIT Frequency
Adjust coupling to dark resonatorsand frequencies of dark resonatorsto modify n() dispersion
9.5 10 10.5 11
0
2
4
6
8
10
Frequency (GHz)
n
(n)(n)
L. Zhang, T. Koschny, and C. Soukoulis (Iowa State Univ.)
6
Experimental SetupMetamaterial-Induced Transparency
CryogenicDewar
X-bandWaveguideSample
NetworkAnalyzer
CoaxialCable
1 2
7
0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5
0 .2
0 .4
0 .6
0 .8
1 .0
0 .0 0 .5 1 .0 1 .5 2 .0 2 .5 3 .0 3 .5
0 .2
0 .4
0 .6
0 .8
1 .0
00
1()
2()
1()
2() ~ 1/
i
Superconductor Electrodynamics
“binding energy” of Cooper pair (100 GHz ~ few THz)
T = 0ideal s-wave
/0iiXRZ sss Surface Impedance (> 0)
Normal State
11
0 1
2 ss XR
Superconducting State ( < 2)
01 0~ ss XR
Penetration depth(0) ~ 20 – 200 nm
nsem
Finite-temperature: Xs(T) = L = (T) → ∞ as T →Tc
Narrow wire or thin film of thickness t : L(T) = (T) coth(t/(T)) → 0 2(T)/tKinetic Inductance
Superfluid density2 ~ m/ns
T
ns(T)
Tc00
/2
Normal State (T > Tc)(Drude Model)
1/
EJ
T
1(T)
Tc00
n
8
Experimental ResultsMetamaterial-Induced Transparency
Nb / Cu MM-EIT sample (first generation) in Cu waveguide
9.70 9.75 9.80 9.85 9.90
-25
-20
-15
-10
-5
0
5
Frequency (GHz)
Tra
nm
siss
ion
|S21
|/|S
21|m
ax (
dB
)
-40
-30
-20
-10
0
10
20
30
40
50
Un
calib
rate
d G
rou
p D
ela
y (ns)
EIT bandwidth (3 dB) = 7.5 MHz (~ 0.1%)
Pin = -30 dBmT = 4.6 K
d
d 12~
9
9.68 9.70 9.72 9.74 9.76 9.78 9.80 9.82 9.84 9.86 9.88
-40
-35
-30
-25
-20
-15
Tra
nsm
issi
on
|S21
| (d
B)
f (GHz)
4.9 K 5 K 6 K 7 K 7.5 K 7.8 K 8 K 8.2 K 8.4 K 8.5 K 8.6 K 8.7 K 8.75 K 8.8 K 8.83 K 8.86 K 8.89 K 8.92 K 8.95 K 8.98 K 9 K 9.04 K 9.1 K 9.2 K 9.3 K
Frequency (GHz)
Tra
nsm
issi
on |S
21|/|
S21
|max
(dB
)0
-5
-10
-15
-20
-25
Superconducting Metamaterial-Induced TransparencyEffect of Temperature on Transmission
5 6 7 8 99.76
9.77
9.78
9.79
f 0 (p
eak) (
GH
z)
T(K)Temperature (K)
f 0(p
eak
) (G
Hz)
5 6 7 8 9-22
-20
-18
-16
-14
|S21
| peak
(d
B)
T(K)Temperature (K)
|S21
| (p
eak
) /|S
21| m
ax(p
eak
) (d
B)
0
-2
-4
-6
-8
10
Superconducting Metamaterial-Induced TransparencyEffect of Temperature on Group Delay
9.72 9.74 9.76 9.78 9.80 9.82 9.84 9.860
10
20
30
40
50
60
70
Un
calib
rate
d G
rou
p D
elay
(n
s)
Frequency (GHz)
4.9 K_smt 7 K_smt 7.8 K_smt 8.2K_smt 8.4 K_smt 8.6 K_smt 8.7 K_smt 8.75 K_smt 8.8 K_smt 8.83 K_smt 8.86 K_smt 8.89 K_smt 8.92 K_smt 8.95 K_smt 8.98 K_smt 9 K_smt 9.1 K_smt 9.2 K_smt 9.3 K_smt
Pin = -30 dBm
5 6 7 8 99.76
9.77
9.78
9.79
Temperature (K)
f 0 (p
eak) (
GH
z)
5 6 7 8 935
40
45
50
55
60
65
70
Temperature (K)
Pea
k G
rou
p d
elay
(n
s)
11
Experimental ResultsMetamaterial-Induced Transparency
Switching/Limiting Behavior at High Power
The “transparencywindow” switchesoff between +17 and+18 dBm
9.70 9.75 9.80 9.85 9.90
-25
-20
-15
-10
-5
0
5
T= 4.24 K
Tra
nsm
issi
on
|S21
|/|S
21|m
ax (
dB
)
Frequency (GHz)
P= -30 dBm P= -10 dBm P= 17dBm P= 18dBm P= 20dBm
12
RF Power Dependence of Superconducting EIT Features
To investigate the RF power dependence, we examine the RF currentdistributions in the superconducting parts of the sample using Laser Scanning Microscopy (LSM)
1 mm
T = 79.5 Kf = 5.2133 GHzP = - 6 dBm
10 V
0 V
8.5 mm
RF photoresponse~ Jrf
2(x, y) Scanned Area
RF inputRF output
YBCO Ground Plane
YBCO Ground Plane
STO Substrate
240 nm thick film
LAO
ff0
|S21(f0)|2
|S21(f0)|2laser OFF
laser ON
resonator transmission
|S12|2 ~ [ JRF(x,y)]2 A
PoutPin
modulatedlaser
See A. P. Zhuravel, et al.,J. Appl. Phys. 108, 033920 (2010)
13
f = 9.63 GHz; P = 18 dBm; T = 7 K
LSM Image of Superconducting RF Currents in EIT sample @ 10 GHz
Upper Nb split ring
Bottom
Geometry 2D LSM image
Focus on this cornerNb split ring
Cu stripe
Current flow numerical simulation, L. Zhang, et al. (Ames)
C. Kurter, et al., arXiv:1008.2020
14
RF Power Dependence of LSM Photoresponse in a Corner of the Nb Split Ring
15 dBm 20 dBm
20.8 dBm 21 dBm 22 dBm
20.6 dBm
2~ RFJ
Quartzsubstrate
Nb film
100 m
100 m
15
Future Directions forSuperconducting EIT Metamaterials
Calibrated and de-embedded S21 and group delay measurements
Rounded-corner samples for better tunability at high power
16
Conclusions
Demonstrated Superconducting Metamaterial-Induced TransparencyTunable with variable Kinetic Inductance and RF magnetic fields
Demonstrated Tunability of features:Temperature tuning (kinetic inductance → plasmonic regime)RF Magnetic Field tuning (magnetic Abrikosov vortices, JRF peaks)
Superconducting Metamaterials Review Article (J. of Optics, in press):arXiv:1004.3226
Work Funded by NSF, ONR.
17
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Stirling cycle cryocooler
MTBF > 106 hours
2.8 kg92 mm OD x 300 mm
5W cooling power @ 77 K
STI “AmpLink” Filter1850 – 1910 MHzPCS band
CryoCoolers and CryoPackaging
Small, inexpensive and reliable cryocoolers are available
Many companies buildcryo-cooled microwaveand high-speed digital
products
18
19
Outline
Losses in Metamaterials
Review article on Superconducting Metamaterials (J. of Optics) arXiv:1004.3226
Brief Review of Superconductor Electrodynamics
New Features Enabled by Superconductivity
Low loss (+ inductance) enables very compact ‘atoms’
New sources of inductance
New sources of nonlinearity and gain
New ‘Atoms’
Some Novel Applications of Superconducting Metamaterials
Future Prospects + Conclusions
20
Why Superconducting Metamaterials?
The exciting novel applications of metamaterials:Flat-slab Imaging“Perfect” ImagingCloaking DevicesIllusion Opticsetc. …
SUPERCONDUCTING METAMATERIALS: Can achieve these requirements!
… have strict REQUIREMENTS on the metamaterials:Low LossesUltra-small size “atoms” (size << wavelength) Tunability / Texturing of the index of refraction n
CloakingDevices
(Engheta, Leonhardt,Pendry, Milton)
LHMRHM RHM
Pointsource “perfect image”
Flat LensImaging
Illusion Optics (Lai)
21
Outline
Losses in Metamaterials
Brief Review of Superconductor Electrodynamics
New Features Enabled by Superconductivity
Low loss (+ inductance) enables very compact ‘atoms’
New sources of inductance
New sources of nonlinearity and gain
New ‘Atoms’
Some Novel Applications of Superconducting Metamaterials
Future Prospects + Conclusions
22
T
1(T)
Tc00
n
23
0 .99 1 .00 1 .01 1 .02
50 00
0
50 00
10 00 0
15 00 0
20 00 0
24
0 .98 0 .99 1 .00 1 .01 1 .020
50
10 0
15 0
Frequency
Ab
sorp
tion
2 = 1 x 10-7
2 = 1 x 10-3
2 = 1 x 10-2
1 = 4 x 10-2
25
9.5 10 10.5 11
0
2
4
6
8
10
Frequency (GHz)
n
(n)(n)
26
Experimental ResultsMetamaterial-Induced Transparency
9.65 9.70 9.75 9.80 9.85 9.90 9.95
-60.0n
-50.0n
-40.0n
-30.0n
-20.0n
-10.0n
0.0
10.0n
20.0n Pinput= -30 dBm,T=4.6KIFBW=300 Hz
groupDelay
Frequency (GHz)
Gro
up D
elay
(se
c)
-32
-30
-28
-26
-24
-22
-20
-18
-16
-14
-12
-10
-8
-6
s21MAG
Transm
ission |S21 | (dB
)
This includestransmission lossesin cold cables andwaveguide
Nb / Cu MM-EIT sample (first generation) in Cu waveguide
27
Experimental ResultsMetamaterial-Induced Transparency
Switching/Limiting Behavior at High Power
9.60 9.65 9.70 9.75 9.80 9.85 9.90 9.95-35
-30
-25
-20
-15
-10
-5 Tbath
= 4.24 K|S
21| (
dB
)
f(GHz)
P= -30 dB P= -10 dB P= 17dB P= 18dB P= 20dB
Frequency (GHz)
|S21
| (d
B)
The “transparencywindow” switchesoff between +17 and+18 dBm
28
Laser Scanning Microscopy of RF CurrentsPrinciple of the Measurement
Work with A. Zhuravel (Kharkov) and A. Ustinov (Karlsruhe)
Pout
ff0
|S21(f0)|2
|S21(f0)|2laser OFF
laser ON
co-planar resonator f0 ~ 5.2 GHz
Pin
modulatedlaser
resonator transmission
Local heating produces a change in transmission coefficient proportionalto the local value of JRF
2
J. C. Culbertson, et al. J.Appl.Phys. 84, 2768 (1998)
A. P. Zhuravel, et al., Appl.Phys.Lett. 81, 4979 (2002)
|S12|2 ~ [ JRF(x,y)]2 A
29
1 mm
T = 79.5 Kf = 5.2133 GHzP = - 6 dBm
10 V
0 V
2-D Response Map for RF Current Distribution of a Sample
Fundamental resonance mode (5.2 GHz)
8.5 mm
RF photoresponse~ Jrf
2(x, y) Scanned Area
RF inputRF output
YBCO Ground Plane
YBCO Ground Plane
STO Substrate
240 nm thick film
LAO
30
1 mm
T = 79.5 Kf = 5.2133 GHzP = - 6 dBm
10 V
0 V
8.5 mm
RF photoresponse~ Jrf
2(x, y) Scanned Area
RF inputRF output
YBCO Ground Plane
YBCO Ground Plane
STO Substrate
240 nm thick film
LAO
31
0 1 2 3 4 5 6 7 8 9-2
0
2
4
6
8
10
12
14
16
18
20
22
P r
esp
on
se, a
.u
X, mm
T=79.5 K with 8672 A Generator P=-6 dBm in scale of 8672A Fmod=99.99 kHz
f=5.2133 GHz
Standing Wave JRF Pattern at Fundamental Frequency
2D image
Pho
tore
spon
se (
a.u.
)
62.439.0cos16~ 2 xPRFit:
kfit = 0.39 mm-1
ktheory = 0.42 mm-1
Proof that measured PR ~ JRF2 to first order approx.