Visible wavelength spectral tuning of absorption and circular dichroism of DNA-assembled Au/Ag core-shell nanorod assemblies

Plasmonic nanoparticles have unique properties which can be harnessed to manipulate light at the nanoscale. With recent advances in synthesis protocols that increase their stability, gold-silver core-shell nanoparticles have become suitable building blocks for plasmonic nanostructures to expand the range of attainable optical properties. Here we tune the plasmonic response of gold-silver core-shell nanorods over the visible spectrum by varying the thickness of the silver shell. Through the chiral arrangement of the nanorods with the help of various DNA origami designs, the spectral tunability of the plasmon resonance frequencies is transferred into circular dichroism signals covering the spectrum from 400 nm to 700 nm. Our approach could aid in the construction of better sensors as well as metamaterials with a tunable optical response in the visible region

Riesz-projection based simulation and analysis of resonant photonic devices and machine-learning based parameter optimization

We present Riesz projection based methods relying on contour integration for efficiently computing quasi-normal modes and modal expansions of near-field and far-field physical quantities. We use a finite-element method based implementation of these methods for the analysis of nanophotonic resonators for quantumoptics applications. We use Bayesian optimization methods for finding best geometry parameters yielding, e.g., resonators with maximized quality factor