Xiang Zhang ’s Group Department of Mechanical and Aerospace Engineering University of California at Los Angeles California Nano System Institute (CNSI) MURI Metamaterial Internal Meeting

Outline Micro-structured Magnetic Resonators (In collaboration with Willie Padilla, David Smith, Dimitri Basov) Plasmonic Nanolithography

Micro-structured Magnetic Resonators 50um Fabricated Sample L:26m, S:10m G: 2m, W:4m, 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 Resonance Die Design (THz) Experiment (THz) D ±0.07 D ±0.05 D ±0.15  =30 o FTIR oblique reflectance (In collaboration with Willie Padilla, David Smith, Dimitri Basov)

Bi-anisotropic Effect Orientation Dependence?  =30 o IRIR I0I0 E or H symmetric asymmetric

Orientation Effect Ellipsometric Ratio Effort ongoing for extraction of the Bi-anisotropy (In collaboration with Willie Padilla, David Smith, Dimitri Basov)

Substrate Choices X-cut quartz (400 μm) Si wafer (500 μm) Fused quartz (400 μm) transmissivity Wavenumber (1/cm) Freq.=1.2 THz 1. At 1.2 THz (resonance frequency), T fused quartz =75% 2. Between 0.6 THz~1.5THz, T fused quartz >T Si-wafer >T x-cut quartz 3. Fused quartz possesses higher transmissivity in interested band.

Conclusion - We observe the orientation issue in FTIR measurement (in corporation with UCSD) - Fused quartz has been proved to have higher transmissivity Future 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 Background

Our Goal : UV Plasmonic Lithography To explore surface plasmons enhanced transmission in UV range and demonstrate a novel Plasmonic Nanolithography Schematic of experimental setup Designed exposure wavelength : 364 nm mode(1,0)(1,1)(1,2) Period 220 nm 320 nm 500 nm

Far-Field Transmission Spectra Measurement Results Normalized transmission in UV range is in the scale of the incident light (40 nm hole diameter) 364 nm

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 nm 2 60 nm hole diameter 80 nm hole diameter Sub-100nm features obtained from aperture ~1/6 of the exposing wavelength Sub-100 nm nanolithography

Conclusion Achieve extraordinary strong transmission in UV range Demonstrated sub-100 nm features lithography at the distance 50 nm above the mask Future Work Further enhance the resolution of Plasmonic Nanolithography