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
OutlineOutline
Micro-structured Magnetic ResonatorsMicro-structured Magnetic Resonators(In collaboration with Willie Padilla, David Smith, Dimitri Basov)
Plasmonic NanolithographyPlasmonic Nanolithography
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
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)
Bi-anisotropic Effect
Orientation Dependence?Orientation Dependence?
=30o
IR
I0
E or H
symmetric
asymmetric
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)
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.
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
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
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
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
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
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
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