Low-Loss Plasmonics with Nanostructured Potassium and Sodium-Potassium Liquid Alloys.

Alkali metals have low optical losses in the visible to near-infrared (NIR) compared with noble metals. However, their high reactivity prohibits the exploration of their optical properties. Recently sodium (Na) has been experimentally demonstrated as a low-loss plasmonic material.

High-Quality Surface Plasmon Polaritons in Large-Area Sodium Nanostructures.

Sodium (Na) is predicted to be an ideal plasmonic material with ultralow optical loss across visible to near-infrared (NIR). However, there has been limited research on Na plasmonics. Here we develop a scalable fabrication method for Na nanostructures by combining phase-shift photolithography and a thermo-assisted spin-coating process.

Narrowing Plasmon Resonance Linewidth of Au Nanodome Lattices.

Gold hollow nanodomes arranged in hexagonal lattices support surface plasmon polaritons (SPPs) propagating at air-Au interface. The cross-sectional heights of the continuous and hierarchical hexagonal nanodome arrays can be altered by a simple thermal treatment, and the change in nanodome size leads to a significant linewidth narrowing of plasmon resonance because of reduced scattering loss. Taking the variation in the SPP intensities into account, the surface modulation depth is found to be around 100 nm for achieving a longer propagation length of SPP.

Dual spectra band emissive Eu/Mn co-activated alkaline earth phosphates for indoor plant growth novel phosphor converted-LEDs.

This paper reports designing a novel single composition blue/red color illuminating phosphor followed by fabricating "smart" agricultural/horticultural LED lighting. Color-tunable Eu/Mn co-activated alkaline earth phosphates, Na(Sr,Ba)PO and CaMg(PO), are considered, and the stable doping sites for the corresponding activators are identified by using first-principle DFT calculations. We can realize the designated color purity with stable thermal quenching preserved luminescence behavior is induced by the Eu center positioned at different coordination states with intermixed Sr/Ba sites in Na(Sr,Ba)PO hosts.

Interfacial Mode Interactions of Surface Plasmon Polaritons on Gold Nanodome Films.

Hollow metallic nanodome structures were fabricated using anodized aluminum oxide (AAO) nanopores as deposition and sacrificial templates. Individual Au nanodomes inherit the unique shapes of the well-defined AAO membranes whose pedestal cells become square or hexagonal lattices with hemispheres in close proximity. Minimal contact between the hollow nanodomes and the glass substrate provide an identical dielectric medium across the film.

Lasing action in strongly coupled plasmonic nanocavity arrays.

Periodic dielectric structures are typically integrated with a planar waveguide to create photonic band-edge modes for feedback in one-dimensional distributed feedback lasers and two-dimensional photonic-crystal lasers. Although photonic band-edge lasers are widely used in optics and biological applications, drawbacks include low modulation speeds and diffraction-limited mode confinement. In contrast, plasmonic nanolasers can support ultrafast dynamics and ultrasmall mode volumes.

Plasmonic bowtie nanolaser arrays.

Plasmonic lasers exploit strong electromagnetic field confinement at dimensions well below the diffraction limit. However, lasing from an electromagnetic hot spot supported by discrete, coupled metal nanoparticles (NPs) has not been explicitly demonstrated to date. We present a new design for a room-temperature nanolaser based on three-dimensional (3D) Au bowtie NPs supported by an organic gain material.

Liquid plasmonics: manipulating surface plasmon polaritons via phase transitions.

This paper reports the manipulation of surface plasmon polaritons (SPPs) in a liquid plasmonic metal by changing its physical phase. Dynamic properties were controlled by solid-to-liquid phase transitions in 1D Ga gratings that were fabricated using a simple molding process. Solid and liquid phases were found to exhibit different plasmonic properties, where light coupled to SPPs more efficiently in the liquid phase.

Talbot effect beyond the paraxial limit at optical frequencies.

This paper reports the experimental and theoretical investigation of the Talbot effect beyond the paraxial limit at optical frequencies. Au hole array films with periodicity a(0) comparable to the wavelength of coherent illumination λ were used to study the non-paraxial Talbot effect. Significant differences from the paraxial (classical) Talbot effect were observed.

Polarization-dependent multipolar plasmon resonances in anisotropic multiscale au particles.

This paper reports the fabrication and characterization of three-dimensional (3D) multiscale Au particles with different aspect ratios. Increasing the length of the particles resulted in excitation of a longitudinal mode and two different transverse modes having different multipolar orders. The multipolar orders increased for both longitudinal and transverse modes as the aspect ratio increased.

Extraordinary nonlinear absorption in 3D bowtie nanoantennas.

This paper reports that arrays of three-dimensional (3D), bowtie-shaped Au nanoparticle dimers can exhibit extremely high nonlinear absorption. Near-field interactions across the gap of the 3D bowties at the localized surface plasmon resonance wavelengths resulted in an increase of more than 4 orders of magnitude in local field intensity. The imaginary part of the third-order nonlinear susceptibility (Im χ((3))) for the 3D bowtie arrays embedded in a dielectric material was measured to be 10(-4) esu, more than 2 orders of magnitude higher than reported for other metal nanoparticle-dielectric composites.

Enhanced optical transmission mediated by localized plasmons in anisotropic, three-dimensional nanohole arrays.

This paper describes three-dimensional (3D) nanohole arrays whose high optical transmission is mediated more by localized surface plasmon (LSP) excitations than by surface plasmon polaritons (SPPs). First, LSPs on 3D hole arrays lead to optical transmission an order of magnitude higher than 2D planar hole arrays. Second, LSP-mediated transmission is broadband and more tunable than SPP-enhanced transmission, which is restricted by Bragg coupling.