Ultrafast photoluminescence and multiscale light amplification in nanoplasmonic cavity glass.

Interactions between plasmons and exciton nanoemitters in plexcitonic systems lead to fast and intense luminescence, desirable in optoelectonic devices, ultrafast optical switches and quantum information science. While luminescence enhancement through exciton-plasmon coupling has thus far been mostly demonstrated in micro- and nanoscale structures, analogous demonstrations in bulk materials have been largely neglected. Here we present a bulk nanocomposite glass doped with cadmium telluride quantum dots (CdTe QDs) and silver nanoparticles, nAg, which act as exciton and plasmon sources, respectively.

Functionalization of Phosphate and Tellurite Glasses and Spherical Whispering Gallery Mode Microresonators.

Active whispering gallery mode resonators made as spherical microspheres doped with quantum dots or rare earth ions achieve high quality factors and are excellent candidates for biosensors capable of detecting biomolecules at low concentrations. However, to produce quantum dot-doped microspheres, new low melting temperature glasses are sought, which require surface functionalization and antibody immobilization for biosensor development. Here, we demonstrate the successful functionalization of three low melting point glasses and microspheres made of them.

Spontaneous off-stoichiometry as the knob to control the dielectric properties of gapped metals.

Using first-principles calculations and LaTe as an example of an n-type gapped metal, we demonstrate that gapped metals can develop spontaneous defect formation resulting in off-stoichiometric compounds. Importantly, these compounds have different free carrier concentrations and can be realized by optimizing the synthesis conditions. The ability to tune the free carrier concentration allows the tailoring of the intraband and interband transitions, thus controlling the optoelectronic properties of materials in general.

In-Capillary Photodeposition of Glyphosate-Containing Polyacrylamide Nanometer-Thick Films.

The present research reports on in-water, site-specific photodeposition of glyphosate (GLP)-containing polyacrylamide (PAA-GLP) nanometer-thick films (nanofilms) on an inner surface of fused silica (fused quartz) microcapillaries presilanized with trimethoxy(octen-7-yl)silane (TMOS). TMOS was chosen because of the vinyl group presence in its structure, enabling its participation in the (UV light)-activated free-radical polymerization (UV-FRP) after its immobilization on a fused silica surface. The photodeposition was conducted in an aqueous (HO/ACN; 3:1, /) solution, using UV-FRP (λ = 365 nm) of the acrylamide (AA) functional monomer, the ,'-methylenebis(acrylamide) (BAA) cross-linking monomer, GLP, and the azobisisobutyronitrile (AIBN) UV-FRP initiator.

Surprising Eutectics: Enhanced Properties of ZnO-ZnWO from Visible to MIR.

Zinc oxide-zinc tungstate (ZnO-ZnWO ) is a self-organized eutectic composite consisting of parallel ZnO thin layers (lamellae) embedded in a dielectric ZnWO matrix. The electromagnetic behavior of composite materials is affected not only by the properties of single constituent materials but also by their reciprocal geometrical micro-/nano-structurization, as in the case of ZnO-ZnWO . The light interacting with microscopic structural features in the composite material provides new optical properties, which overcome the possibilities offered by the constituent materials.

Optically-active metastable defects in volumetric nanoplasmonic composites.

Metastable defects in semiconductor materials have been well known for decades, but have only recently started to attract attention for their potential applications in information technology. Here, we describe active and passive nanoplasmonic materials with optically active metastable defects that can be switched on or off by cooling with or without laser illumination, respectively. To the best of our knowledge, this is the first report of metastable defects in either passive or active nanoplasmonic materials, and, more generally, in non-semiconducting materials.

Self-Phase-Matched Second-Harmonic and White-Light Generation in a Biaxial Zinc Tungstate Single Crystal.

Second-order nonlinear optical materials are used to generate new frequencies by exploiting second-harmonic generation (SHG), a phenomenon where a nonlinear material generates light at double the optical frequency of the input beam. Maximum SHG is achieved when the pump and the generated waves are in phase, for example through birefringence in uniaxial crystals. However, applying these materials usually requires a complicated cutting procedure to yield a crystal with a particular orientation.

Compendium of natural hyperbolic materials.

Artificially structured hyperbolic metamaterials (HMMs) - uniaxial materials with opposite signs of permittivity for ordinary and extraordinary waves - are one of the most attractive classes of metamaterials. Their existing in nature counterpart natural (homogeneous) hyperbolic materials (NHMs) has several advantages but has not yet been analyzed extensively. Here, based on literature-available data on permittivity as a function of wavelength, we review materials with naturally occurring anisotropy of permittivity in specific wavelength ranges.

Temperature and atmosphere tunability of the nanoplasmonic resonance of a volumetric eutectic-based Bi₂O₃-Ag metamaterial.

Nanoplasmonic materials are intensively studied due to the advantages they bring in various applied fields such as photonics, optoelectronics, photovoltaics and medicine. However, their large-scale fabrication and tunability are still a challenge. One of the promising ways of combining these two is to use the self-organization mechanism and after-growth engineering as annealing for tuning the properties.

Interacting plasmon and phonon polaritons in aligned nano- and microwires.

The availability of macroscopic, nearly periodic structures known as eutectics opens a new path for controlling light at wavelength scales determined by the geometrical parameters of these materials and the intrinsic properties of their component phases. Here, we analyze the optical waveguiding properties of eutectic mixtures of alkali halides, formed by close-packed arrangements of aligned cylindrical inclusions. The wavelengths of phonon polaritons in these constituents are conveniently situated in the infrared and are slightly larger than the diameter and separation of the inclusions, typically consisting on single-crystal wires down to submicrometer diameter.

High-pressure crystallography of rhombohedral PrAlO(3) perovskite.

The evolution of the crystal structure of rhombohedral PrAlO(3) perovskite with pressure has been investigated by single-crystal x-ray diffraction and Raman scattering experiments. The structural evolution as indicated by lattice strains, octahedral tilts, and the distortions of the octahedral AlO(6) and polyhedral PrO(12) groups with increasing pressure, is controlled by the relative compressibilities of the AlO(6) octahedra and the PrO(12) site. Because the AlO(6) octahedra are more compressible than the PrO(12) sites, up to 7.

Structure of YAG crystals doped/substituted with erbium and ytterbium.

Two series of yttrium aluminum garnets doped with erbium and ytterbium ions have been studied by single-crystal X-ray diffraction. The single crystals were obtained by the Czochralski method. The concentration of doping ions was established by the plasma emission spectroscopy method.