Surface Lattice Resonances in 3D Chiral Metacrystals for Plasmonic Sensing.

Chiral lattice modes are hybrid states arising from the chiral plasmonic particles assembled in ordered arrays with opportune periodicity. These resonances exhibit dependence on excitation handedness, and their observation in plasmonic lattices is strictly related to the chiroptical features of the fundamental plasmonic unit. Here, the emergence of chiral surface lattice resonances (c-SLRs) is shown in properly engineered arrays of nanohelices (NHs), fully three dimensional (3D) chiral nano-objects fabricated by focused ion beam processing.

Gallium chiral nanoshaping for circular polarization handling.

In this work we report the local growth of ordered arrays of 3D core-shell chiral nanohelices based on plasmonic gallium metal. The structures can be engineered in a single step using focused ion beam induced deposition, where a Ga ion source is used to shape the metallic nanohelix core, while the dielectric precursor is dissociated to create dielectric shells. The solubility of gallium in the different investigated dielectric matrices controls the core-shell thickness ratio of the nanohelices.

Innovative 3D Microfluidic Tools for On-Chip Fluids and Particles Manipulation: From Design to Experimental Validation.

Micromixers are essential components in lab-on-a-chip devices, of which the low efficiency can limit many bio-application studies. Effective mixing with automation capabilities is still a crucial requirement. In this paper, we present a method to fabricate a three-dimensional (3D) poly(methyl methacrylate) (PMMA) fluidic mixer by combining computer-aided design (CAD), micromilling technology, and experimental application via manipulating fluids and nanoparticles.

Symmetry Breaking in Oligomer Surface Plasmon Lattice Resonances.

We describe a novel plasmonic-mode engineering, enabled by the structural symmetry of a plasmonic crystal with a metallic oligomer as unit cell. We show how the oligomer symmetry can tailor the scattering directions to spatially overlap with the diffractive orders directions of a plasmonic array. Applied to the color generation field, the presented approach enables the challenging achievement of a broad spectrum of angle-dependent colors since smooth and continuous generation of transmitted vibrant colors, covering both the cyan-magenta-yellow and the red-green-blue color spaces, is demonstrated by scattering angle- and polarization-dependent optical response.

Tailoring chiro-optical effects by helical nanowire arrangement.

In this work, we experimentally investigate the chiro-optical properties of 3D metallic helical systems at optical frequencies. Both single and triple-nanowire geometries have been studied. In particular, we found that in single-helical nanostructures, the enhancement of chiro-optical effects achievable by geometrical design is limited, especially with respect to the operation wavelength and the circular polarization conversion purity.

Exciton-Plasmon Coupling Enhancement via Metal Oxidation.

In this paper, we report on the effect of metal oxidation on strong coupling interactions between silver nanostructures and a J-aggregated cyanine dye. We show that metal oxidation can sensibly affect the plexcitonic system, inducing a change in the coupling strength. In particular, we demonstrate that the presence of oxide prevents the appearance of Rabi splitting in the extinction spectra for thick spacers.