Optical confinement in the nanocoax: coupling to the fundamental TEM-like mode
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Updated: Dec 3, 2025

Fabrication of 1-D Photonic Crystal Cavity on a Nanofiber Using Femtosecond Laser-induced Ablation
Published on: February 25, 2017
Abstract:
The nanoscale coaxial cable (nanocoax) has demonstrated optical confinement in the visible and the near infrared. We report on a novel nanofabrication process which yields optically addressable, sub-µm diameter, and high aspect ratio metal-insulator-metal nanocoaxes made by atomic layer deposition of Pt and Al2O3. We observe sub-diffraction-limited optical transmission via the fundamental, TEM-like mode by excitation with a radially polarized optical vortex beam. Our experimental results are based on interrogation with a polarimetric imager. Finite element method numerical simulations support these results, and their uniaxial symmetry was exploited to model taper geometries with both an electrically large volume, (15λ)3, and a nanoscopic exit aperture, (λ/200)2.
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