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Nanostructured metal-insulator-metal metamaterials for refractive index biosensing applications: Design, fabrication, and characterization


Khai Q. Le*, Quang Minh Ngo, Truong Khang Nguyen

Source title: 
IEEE Journal of Selected Topics in Quantum Electronics, 23(2): 6900506, 2017 (ISI)
Academic year of acceptance: 

Nanofabrication of nanostructured metal-insulator-metal metamaterial (NMIM2) by the electron beam lithography and the liftoff technique is reported in this paper. The NMIM2 consists of periodic arrays of gold (Au) nanotriangles deposited on a gold layer (acting as a mirror) separated by a thin dielectric insulator. Such an NMIM2 stack was fabricated on a silicon wafer. Reflection of the NMIM2 was measured by the Fourier transform infrared spectroscope. The experimental measurement for reflection coefficients are in good agreement with the full-wave finite-different time-domain simulation results. At resonance, we numerically observed a strong field localized inside the gap between the Au nanostructures and the Au mirror, resulting in a strong confinement of incoming light within the insulator spacer and, thus, a pronounced absorption at telecommunication wavelengths. This resonant spectral response is investigated for sensitive label-free refractive index biosensing applications.