nl5028183_si_003.avi (14.76 MB)
Experimental Realization of a Polarization-Independent Ultraviolet/Visible Coaxial Plasmonic Metamaterial
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posted on 2015-12-17, 05:47 authored by M. A. van de Haar, R. Maas, H. Schokker, A. PolmanWe
report the experimental realization of an optical metamaterial
composed of a hexagonal array of coaxial plasmonic metal/insulator/metal
waveguides that shows strong polarization-independent optical mode
index dispersion in the ultraviolet/blue. The metamaterial is composed
of silicon coaxes with a well-defined diameter in the range of 150–168
nm with extremely thin sidewalls (13–15 nm), embedded in a
silver film, fabricated using a combination of electron beam lithography,
physical vapor deposition, reactive ion etching, and focused ion beam
polishing. Using a Mach–Zehnder interferometer the phase advance
is measured on several metamaterial samples with different dimensions
in the UV/visible part of the spectrum. For all geometries the spectral
features as well as the geometry dependence of the data correspond
well with numerical finite-difference time domain simulations and
the calculated waveguide dispersion diagram, showing a negative mode
index between 440 and 500 nm.