1 research outputs found
High-Order Hilbert Curves: Fractal Structures with Isotropic, Tailorable Optical Properties
Fractals
are promising candidates as nonperiodic, nonresonant structures
exhibiting a homogeneous, isotropic, and frequency-independent effective
optical response. We present a comprehensive optical investigation
of a metallic Hilbert curve of fractal order <i>N</i> =
9 in the visible and near-infrared spectral range. Our experiments
show that high-order fractal nanostructures exhibit a nearly frequency
independent reflectance and an in-plane isotropic optical response.
The response can be simulated in the framework of a simple effective
medium approximation model with a limited number of parameters. It
is shown that high-order Hilbert structures can be considered as a
“transparent in-plane metal”, the dielectric function
of which is modified by the filling factor <i>f</i>, hence
creating a tunable conductive effective metal with tailorable plasma
frequency and variable reflectance without going through an insulator-to-metal
transition