UCLA-MURI Teleconference
UCSD Program
Sheldon Schultz and David R. Smith
Anthony Starr (Visiting Researcher)
David C. Vier (Senior Researcher)
David Schurig (Graduate Student)
Physics Department, University of California, San Diego
1
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Research Topics: Theory and Modeling
of Wave Propagation in Metamaterials
I. Material Interfaces Designed for Novel Properties
• Magnetic mirror metamaterials
• Design of TEM magnetic mirror mode
waveguide
• Cavities with magnetic mirror walls
• Surface plasmon characterization
2
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Research Topics: Subwavelength
Focusing by “perfect lens”
I. Steady-state conditions
• Consequences of deviation from ideal parameters
• The transfer function
• Two source resolution
I. Time dependence
• Response to source fields turned on instantaneously
• Transient response at long and short times
3
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Collaborations: MIT/UCSD/IC
4
•
MIT and Imperial College groups have predicted that
photonic band gap structures can produce negative
refraction.
•
A Design has been completed for a material with Re(e)=9,
for operation at 10 GHz.
•
Chen’s group (MIT) is making compacted powder into e=9
material.
•
UCSD group will make the microwave measurements.
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Collaborations: MIT/UCSD/IC
• Initial test sample material is very fragile- making
traditional cavity perturbation e’ and e” sample
volume/geometry highly variable.
• Tests are underway to verify whether irregular
shaped volumes of calibration materials give selfconsistent e’ and e” values.
5
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Collaborations: UCSD/UCLA
• UCLA group has fabricated an initial metamaterial
sample operational at ~1 THz.
•
6
UCSD (Basov group) has performed initial
measurements on the sample.
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Summary of Measurements on the
UCLA Wire Structure
Willie Padilla
Professor Dimitri Basov
7
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Far Infrared Spectroscopy
Temperature
4K - 500K
Energy
125µeV - 6eV
30GHz-1500THz
Field
Up to 9 Tesla
8
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
FIR Spectroscopy
R(ω) ⇒ Kramers-Kronig relation ⇒ Θ(ω)
Complex material parameters
R(ω)
⇒
Θ(ω)
σ1+iσ2, ε1+iε2, etc…
9
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
The Sample
10
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Results
•The general curve shape is in
accord with a plasma edge. Plasma
frequency occurring at about 1THz.
•Resonances correspond to modes
and their harmonics (as marked),
probably due to the length of the
wires ~1mm.
•Shaded area signifies the limit of
measurement capability due to
sample size.
•Measurement is not
normalized. Measurements
can be normalized, but this requires
larger samples for transmission
measurements.
11
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Suggestions for Future Samples
•Push for higher plasma frequency such that beginning of plasma
edge and can be seen directly (minimum of 2THz).
•Gold coat all samples. This will ensure that the samples do not
oxidize and become non-conducting.
•Samples with longer wires (1.5mm) would help to better
understand the resonances seen in reflectance (as they would shift
in frequency).
•Samples consisting of one row of wires, and substrate alone with
no wires will help in associating the features seen in reflectance
with wires, background, etc…
12
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Resolution Limits on the Perfect Lens
1000
Resolution is limited
by losses, deviations
from (-1,-1), and
periodicity.
µ' = -2
-1.5
µ = µ' + 0.001 i
ε = -1 + 0.001 i
-1.2
100
-1.1
d/λ= 0.1
-1.05
-1.02
10
-1.01
-1.002
|τe
z
ik d
|
-1.005
ln δµ λ
λ
R≡
=−
λmin
2π d
-1.001
1
-1
0.1
0.01
0
2
4
6
8
k /k
x
13
10
12
14
16
0
http://physics.ucsd.edu/~drs
λ
1  λ2  λ
R≡
ln  2 4 
=
λmin 2π  a ∆  d
May 10, 2002
UCLA-MURI Teleconference
Parametric Studies of Imaging
µ
µ
µ
µ
µ
10
µ
0.08
ε
ε
100
0.06
10
1
0.04
1
0.1
0.02
0.1
ε
Intensity
T(z0,z0+2d)
Intensity
100
ε
ε
µ
µ
T(z0,z0+2d)
ε
ε
0.12
ε
0.1
0.08
0.06
0.04
0.02
0
2
4
6
8
kx / k 0
14
10
12
14
- 0.1
- 0.05
0
x / λ0
0.05
0.1
0
2
4
6
8
kx / k0
http://physics.ucsd.edu/~drs
10
12
14
- 0.1
- 0.05
0
0.05
0.1
x / λ0
May 10, 2002
UCLA-MURI Teleconference
Reflection Properties of Surfaces
We study the reflectance properties of waves incident on a
metamaterial, tuning from PEC to PMC.
Assuming Debye and Lorentz
forms for e and m, we see as a
function of frequency that a
metamaterial can tune from
PEC to PMC. Losses produce
deviations from this behavior
(as shown).
15
http://physics.ucsd.edu/~drs
May 10, 2002
UCLA-MURI Teleconference
Surface Plasmons on Metamaterials
1
2 3 4
1
0.8
0.6
0.4
0.2
-a
16
0
9
d
http://physics.ucsd.edu/~drs
10
11
12
May 10, 2002