1. Superconducting Electromagnetic
Metamaterials
Steven M. Anlage, Michael Ricci, Nathan Orloff
Fermilab May, 2007
Work Funded by NSF/ECS

2. Negative Refraction: Consequences
Left-Handed or Negative Index of Refraction Metamaterials
e < 0 AND m < 0 Veselago, 1967
Propagating waves have index of refraction n < 0
 Phase velocity is opposite to Poynting vector direction
Negative refraction in Snell’s Law: n1 sinq1 = n2 sinq2
Flat lens with no optical axis
Converging Lens → Diverging Lens
and vice-versa
“Perfect” Lens (Pendry, 2000)
Reverse Doppler Effect
Reversed Čerenkov Effect
Radiation Tension
LHM
RHM
Point
source
“perfect image”
Flat Lens
Imaging
Cloaking
Devices
(Engheta, Leonhardt,
Pendry, Milton)
V. G. Veselago, Usp. Fiz. Nauk 92, 517 (1967)
[Eng. Trans.: Sov. Phys. Uspekhi 10, 509 (1968)]

3. Metamaterial vs Photonic Crystal
wavelength l
elementary
units or
“atoms”
Create an “effective medium,”
using engineered “atoms,” with
macroscopic eeff, meff, n properties
Metamaterial a
Photonic
Crystal
a ~ l
Use constructive and destructive
interference to engineer properties
of light →
band structure
band gaps
defect states
negative group velocity …

4. Superconducting Metamaterials
How to make them: Step 1
All-Nb X-band waveguide + couplers
Nb X-band waveguide
(22.86 x mm2)
Tc = 9.25 K
Thanks to
P. Kneisel
@ JLab
4.57 mm
Nb Wires
0.25 mm dia.
Tc = 9.25 K
What are we doing?
10.2 mm
22.9 mm
Nb Wires

5. Superconducting Metamaterials
How to make them: Step 2
Nb film, ~ 200 nm thick
0.89 cm
3.0 cm
2.36 mm
0.3 mm
0.154 mm
Nb SRR
200 nm thick
on Quartz (350 mm)
Tc = 8.65 K B E k

6. Overlap of eeff < 0 and meff < 0 to make n < 0
216 SRRs in
out
Negative Index Passband in a Superconducting Metamaterial
216 SRRs in a 12-cell wire array, 9 cm long
Overlap of eeff < 0 and meff < 0 to make n < 0
Increasing temperature
Transmission
Superconducting
Normal
Metal
Negative
Index of
Refraction
wire array
plasma edge

7. Metamaterials: Novel Applications
Thin SubWavelength Cavity Resonators (Engheta, 2002)
For a resonance in the z-direction:
New possibility – zero net phase winding
p = 0 “zeroth order resonance” z
0th resonance condition independent of d1 + d2
and depends only on d1/d2
RHM
LHM
n1>0
n2<0
Conducting planes
p can also be a negative integer!

8. Split-Ring Resonators
Implementation of an LHM Compact Waveguide
Novel LHM Pass Band
Waveguide
2 cm
e < 0
Transmission |S21| (dB)
e > 0
Split-Ring Resonators
(SRRs)
Provide m < 0 at 350 MHz
Frequency (GHz)
Hrabar, et al., 2005
Measured transmission |S21| parameter of miniaturized waveguide (a = 16 mm)
filled with metamaterial based on capacitively loaded rings. The ordinary cutoff of the
waveguide is 7 GHz, while the SRRs produce a LHM pass band at 350 MHz.

9. SC metamaterials papers: Appl. Phys. Lett. 87, 034102 (2005)
Conclusions
Negatively Refracting Metamaterials offer opportunities for a new kind of optics
Negative Index of Refraction
Flat Lens Imaging
Amplification of Evanescent Waves
“Super Lenses”
There are many new Emerging Applications
Compact (dual TL) structures with enhanced performance
Composite LHM/RHM materials with unique field structures
New antenna structures
Novel optics / NIR lithography
Recovering Evanescent fields
SC metamaterials papers: Appl. Phys. Lett. 87, (2005)
Appl. Phys. Lett. 88, (2006)

10. What Else Can Be Done? Higher Frequencies Smaller size “atoms”
Low-Loss Limited only by SC gap frequency
Nb: 2D/ħ ~ 1 THz
HTS: 2D/ħ ~ 10 THz
Size Scaling
Losses remain small as dimensions shrink
Enhanced Inductance Tricks:
Thinner films – Enhanced Kinetic Inductance
Josephson Junctions – Enhanced and tunable inductance
Novel Effects Unique to Superconductors:
SQUID – the ultimate low-loss tunable SRR
Josephson Junction Array collective dynamics

11. Metamaterials: Novel Applications
Amplification of evanescent waves
Super-resolution imaging
Perfect absorber condition
Reversed Doppler effect
Tunable reflection phase properties
New guided mode structures
Reversed optics
Compact size and light weight electromagnetic structures

12. Metamaterials: Novel Antennas
Directional
Antenna
with n ~ 0
A point source embedded in a metamaterial with n~0 will produce a directed beam
nearly normal to the metamaterial/vacuum interface. From [Enoch2002].
Super-Efficient Electrically-small
Dipole Antenna (ℓ << l)
RHM
LHM
Small dipole
antenna
Ziolkowski (2003)
LHM shell compensates Im[ZAnt]
Factor of 74 improvement in PRad at
10 GHz with l/1000 antenna

13. Split-Ring Resonators
Implementation of an LHM Compact Waveguide
Novel LHM Pass Band
Waveguide
2 cm
e < 0
Transmission |S21| (dB)
e > 0
Split-Ring Resonators
(SRRs)
Provide m < 0 at 350 MHz
Frequency (GHz)
Hrabar, et al., 2005
Measured transmission |S21| parameter of miniaturized waveguide (a = 16 mm)
filled with metamaterial based on capacitively loaded rings. The ordinary cutoff of the
waveguide is 7 GHz, while the SRRs produce a LHM pass band at 350 MHz.

14. RHM/LHM/RHM resonator is 86% smaller
Implementation of an LHM Compact Resonator
RHM/LHM/RHM
Conventional RHM
Both resonate at 1.2 GHz
RHM/LHM/RHM resonator is 86% smaller
Scher, et al., 2004
Microstrip Resonators
RHM Transmission Lines
LHM Transmission Line
(Dual structure)

15. Negative Index Microwave Circuits
Dual Transmission Lines with NIR
concepts are leading to a new class
of microwave devices
Compact couplers, resonators,
antennas, phase shifters have been
demonstrated
1.9 GHz 0th-order resonator
T. Itoh, et al., UCLA