ph0c00266_si_001.pdf (1.2 MB)
Genetic-Algorithm-Aided Meta-Atom Multiplication for Improved Absorption and Coloration in Nanophotonics
journal contribution
posted on 2020-06-30, 19:13 authored by Changxu Liu, Stefan A. Maier, Guixin LiFor
a repertoire of nanophotonic systems, including photonic crystals,
metasurfaces, and plasmonic structures, unit cell with a single element
is conventionally used for the simplicity of design. The extension
of the unit cell with multiple meta-atoms drastically enlarges the
parameter space and consequently provides potential configurations
with improved device performance. Simultaneously, the multiplication
does not induce additional complexity for lithography-based fabrications.
However, the substantially increased number of parameters makes the
design methodology based on physical intuition and parameter sweep
impractical. Here, we show that expanding the number of meta-atoms
in the unit cell significantly improves the performance of nanophotonic
systems by the virtue of a genetic algorithm-based optimizer. Our
approach includes physical intuition endowed in the geometry of meta-atoms,
providing additional physical understanding of the optimization process.
We demonstrate two photonic applications, including prominent enhancement
of a broadband absorption and enlargement of the color coverage of
plasmonic nanostructures. Not limited to the two proof-of-concept
demonstrations, this methodology can be applied to all meta-atom-based
nanophotonic systems, including plasmonic near-field enhancement and
nonlinear frequency conversion, as well as a simultaneous control
of phase and polarization for metasurfaces.