Rational design of an integrated directional coupler for wideband operation.

We consider a design procedure for directional couplers for which the coupling length is approximately wavelength-independent over a wide bandwidth. We show analytically that two coupled planar waveguides exhibit a maximum in the coupling strength, which ensures both wideband transmission and minimal device footprint. This acts as a starting point for mapping out the relevant part of phase space.

Plasmonic interactions: from molecular plasmonics and Fano resonances to ferroplasmons.

Plasmon interactions are a subject of great interest from both the technological as well as the fundamental points of view. In this Perspective, we outline the great variety of physical phenomena that are produced by the interactions of localized surface plasmon resonance with molecular excitons; with other plasmonic nanostructures, particularly the Fano effect; and with nonplasmonic nanoparticles, such as the just-reported interaction with ferromagnetic nanoparticles. The theoretical as well as experimental challenges remaining to be elucidated are discussed.

One-step/one-pot decoration of oxide microparticles with silver nanoparticles.

Hypothesis: Heterogeneous nucleation of silver oxide (Ag2O) onto oxide microparticles (OMPs) followed by spontaneous thermal decomposition produce nanostructures made of OMPs decorated with silver nanoparticles (OMP|AgNPs).

Experiments: Colloidal chemistry methods have been used to produce the decoration of OMPs with silver nanoparticles (AgNPs), by carrying out the Ag2O precipitation/thermal decomposition. The process is driven in water enriched acetone medium containing NaOH, NH3, AgNO3 and SiO2MPs as substrate.