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Xiang Zhang ’s GroupXiang Zhang ’s Group
Department of Mechanical and Aerospace EngineeringUniversity of California at Los Angeles
California Nano System Institute (CNSI)
MURI MetamaterialMURI Metamaterial
Internal MeetingInternal Meeting
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OutlineOutline
Micro-structured Magnetic ResonatorsMicro-structured Magnetic Resonators(In collaboration with Willie Padilla, David Smith, Dimitri Basov)
Plasmonic NanolithographyPlasmonic Nanolithography
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Micro-structured Magnetic ResonatorsMicro-structured Magnetic Resonators
50um
Fabricated Sample
L:26m, S:10mG: 2m,W:4m, d=L+S=36 μm
quartz
Cu, 3um
Ti, 20nm
We have successfully synthesized Micro-magnetic Resonators
- Minimal features: 2um
- Ring thickness: 3um
- Target Working Frequency: 0.7-2THz
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Scalable Magnetic ResonanceScalable Magnetic Resonance
DieDesign
(THz)Experiment
(THz)
D1 1.22 1.27±0.07
D2 0.88 0.96±0.05
D3 0.91 0.85±0.15
=30o
FTIR oblique reflectance
(In collaboration with Willie Padilla, David Smith, Dimitri Basov)
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Bi-anisotropic Effect
Orientation Dependence?Orientation Dependence?
=30o
IR
I0
E or H
symmetric
asymmetric
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Orientation EffectOrientation Effect
30 40 50 60
1.0
1.2
1.4
1.6
1.80.9 1.2 1.5 1.8
THz
(cm-1)
|Rs/R
p|
Asym Sym
Ellipsometric Ratio
Effort ongoing for extraction of the Bi-anisotropy
0.6 0.9 1.2 1.5 1.8 2.1 2.40.0
0.2
0.4
0.6
0.8
P-Sym S-Sym
Ref
lect
ion
Frequency (THz)
0.0
0.2
0.4
0.6
0.80.6 0.9 1.2 1.5 1.8 2.1 2.4
P-Asym S-Asym
(In collaboration with Willie Padilla, David Smith, Dimitri Basov)
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Substrate ChoicesSubstrate Choices
X-cut quartz (400 μm)
Si wafer (500 μm)
Fused quartz (400 μm)
transm
issivity
Wavenumber (1/cm)
Freq.=1.2 THz
1. At 1.2 THz (resonance frequency), Tfused quartz =75%
2. Between 0.6 THz~1.5THz, T fused quartz>TSi-wafer>T x-cut quartz
3. Fused quartz possesses higher transmissivity in interested band.
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ConclusionConclusion- We observe the orientation issue in FTIR
measurement (in corporation with UCSD)
- Fused quartz has been proved to have higher transmissivity
Future workFuture work- Investigate the bi-anisotropic effect
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Ebbesen TW, et al., 1998
Schematic of hole arrays structure
0.9 µm
150nm
200nm
Zero-order transmission spectrum of hole arrays
Discovery of extraordinary transmission through sub-wavelength hole arrays in infrared and visible range
BackgroundBackground
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Our Goal : UV Plasmonic LithographyOur Goal : UV Plasmonic Lithography
To explore surface plasmons enhanced transmission in UV range
and demonstrate a novel Plasmonic Nanolithography
Schematic of experimental setup
md
md
ji
aji
22
0),(
Designed exposure wavelength : 364 nm
mode (1,0) (1,1) (1,2)
Period220 nm
320 nm
500 nm
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Far-Field Transmission Spectra Measurement ResultsFar-Field Transmission Spectra Measurement Results
Normalized transmission in UV range is in the scale of the incident light
(40 nm hole diameter)
364 nm
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1 µm
Lithography results for different periods Lithography results for different periods
pattern size ~120 nm, period 500 nm pattern size ~250 nm, period 320 nm
Achieve resolvable exposed results from larger periodicity samples
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exposure time 7 sec (56 mJ/cm ), spacer thickness 50 nm, period 500 nm2
60 nm hole diameter 80 nm hole diameter
Sub-100nm features obtained from aperture ~1/6 of the exposing wavelength
Sub-100 nm nanolithographySub-100 nm nanolithography
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ConclusionConclusion
Achieve extraordinary strong transmission in UV range
Demonstrated sub-100 nm features lithography at the distance 50 nm above the mask
Future WorkFuture Work
Further enhance the resolution of Plasmonic Nanolithography