Zahyun Ku

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In order to more clearly observe the bianisotropic effects due to fabrication-induced structural asymmetries in negative-index metamaterials based on a fishnet structure, it is necessary to measure the optical properties with symmetric substrate and superstrate bounding layers. This is accomplished in this report using an index-matching fluid and identical(More)
Interferometric lithography (IL) is a powerful technique for the definition of large-area, nanometer-scale, periodically patterned structures. Patterns are recorded in a light-sensitive medium, such as a photoresist, that responds nonlinearly to the intensity distribution associated with the interference of two or more coherent beams of light. The(More)
We demonstrate a nanoscale, subpicosecond (ps) metamaterial device capable of terabit/second all-optical communication in the near-IR. The 600 fs response, 2 orders of magnitude faster than previously reported, is achieved by accessing a previously unused regime of high-injection level, subpicosecond carrier dynamics in the alpha-Si dielectric layer of the(More)
In the past few years, there has been increasing interest in surface plasmon-polaritons, as a result of the strong near-field enhancement of the electric fields at a metal-dielectric interface. Here we show the first demonstration of a monolithically integrated plasmonic focal plane array (FPA) in the mid-infrared region, using a metal with a(More)
Negative-index metamaterials (NIMs) at near infrared wavelengths (~2 mum) are fabricated with circular, elliptical and rectangular holes penetrating through metal/dielectric/metal films. All three NIM structures exhibit similar figures of merit; however, the transmission is higher for the NIM with rectangular holes as a result of an improved impedance match(More)
The effect of a nonzero sidewall angle on the performance of multiple layer fishnet-structure ͑one to three functional layers͒ negative index metamaterials is evaluated experimentally. The fabrication-induced sidewall angle results in a bianisotropy ͑inhomogeneous asymmetry͒ that is significant at optical frequencies. Good agreement is obtained between the(More)
Simulation results of near infrared (100- to 200-THz) fishnet-structure negative-index metamaterials (NIMs) with single and multiple functional layers exhibit bi-anisotropy - inhomogeneous asymmetry - due to the presence of a sidewall-angle. The influence of sidewall-angle resulting from realistic fabrication processes is investigated through the retrieved(More)
This article reports a simple, versatile approach to the fabrication of lithographically defined mesoscopic colloidal silica nanoparticle patterns over large areas using spin-coating, interferometric lithography, and reactive-ion etching. One-dimensional nanoparticle films (bands) and 2D discs, diamonds, and holes with sub-micrometer periodicity, high(More)
We demonstrate an ultrafast (600 fs) dual-band optical switching device using a negative-index metamaterial. A large switching ratio is achieved at both the fundamental (70%) and higher order coupling bands (20%) of the negative-index resonance.
In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed "algorithmic spectrometry". We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The(More)