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