Plasmonics on the slope of enlightenment: the role of transition metal nitrides.

The key problem currently faced by plasmonics is related to material limitations. After almost two decades of extreme excitement and research largely based on the use of noble metals, scientists have come to a consensus on the importance of exploring alternative plasmonic materials to address application-specific challenges to enable the development of new functional devices. Such a change in motivation will undoubtedly lead to significant advancements in plasmonics technology transfer and could have a revolutionary impact on nanophotonic technologies in general.

Refractory plasmonics with titanium nitride: broadband metamaterial absorber.

A high-temperature stable broadband plasmonic absorber is designed, fabricated, and optically characterized. A broadband absorber with an average high absorption of 95% and a total thickness of 240 nm is fabricated, using a refractory plasmonic material, titanium nitride. This absorber integrates both the plasmonic resonances and the dielectric-like loss.

Photothermal heating enabled by plasmonic nanostructures for electrokinetic manipulation and sorting of particles.

Plasmonic nanostructures support strong electromagnetic field enhancement or optical "hot spots" that are accompanied by local heat generation. This heating effect is generally seen as an obstacle to stable trapping of particles on a plasmonic substrate. In this work, instead of treating the heating effect as a hindrance, we utilized the collective photoinduced heating of the nanostructure array for high-throughput trapping of particles on a plasmonic nanostructured substrate.

Local heating with lithographically fabricated plasmonic titanium nitride nanoparticles.

Titanium nitride is considered a promising alternative plasmonic material and is known to exhibit localized surface plasmon resonances within the near-infrared biological transparency window. Here, local heating efficiencies of disk-shaped nanoparticles made of titanium nitride and gold are compared in the visible and near-infrared regions numerically and experimentally with samples fabricated using e-beam lithography. Results show that plasmonic titanium nitride nanodisks are efficient local heat sources and outperform gold nanodisks in the biological transparency window, dispensing the need for complex particle geometries.

Unidirectional spaser in symmetry-broken plasmonic core-shell nanocavity.

The spaser, a quantum amplifier of surface plasmons by stimulated emission of radiation, is recognized as a coherent light source capable of confining optical fields at subwavelength scale. The control over the directionality of spasing has not been addressed so far, especially for a single-particle spasing nanocavity where optical feedback is solely provided by a plasmon resonance. In this work we numerically examine an asymmetric spaser - a resonant system comprising a dielectric core capped by a metal semishell.

Effect of particle properties and light polarization on the plasmonic resonances in metallic nanoparticles.

The resonance behavior of localized surface plasmons in silver and gold nanoparticles was studied in the visible and near-infrared regions of the electromagnetic spectrum. Arrays of nano-sized gold (Au) and silver (Ag) particles with different properties were produced with electron-beam lithography technique over glass substrates. The effect of the particle size, shape variations, period, thickness, metal type, substrate type and sulfidation were studied via transmission and reflectance measurements.