Metallodielectric materials with plasmonic resonances at optical and infrared wavelengths are attracting increasing interest, due to their potential novel applications in the fields of photonics, plasmonics and photovoltaics. However, simple and fast fabrication methods for three‐dimensional bulk plasmonic nanocomposites that offer control over the size, shape and chemical composition of the plasmonic elements have been missing. Here, such a manufacturing method and examples of experimental realizations of volumetric isotropic nanocomposites doped with plasmonic nanoparticles that exhibit resonances at visible and infrared wavelengths are presented. This method is based on doping a low‐melting dielectric material with plasmonic nanoparticles, using a directional glass‐solidification process. Transmission‐spectroscopy experiments confirm a homogenous distribution of the nanoparticles, isotropy of the material and resonant behavior. The phenomenon of localized surface plasmon resonance is also observed visually. This approach may enable rapid and cost‐efficient manufacturing of bulk nanoplasmonic composites with single or multiple resonances at various wavelength ranges. These composites could be isotropic or anisotropic, and potentially co‐doped with other chemical agents, in order to enhance different optical processes.

Due to the development of novel manufacturing technologies and the increasing availability of nano‐/micromaterials, plasmonics has become an emerging field in photonics research. Although the fabrication of metallic elements has already been widely demonstrated, the development of 3D plasmonic materials is progressing slowly. This paper reports the development of a self‐organized, 3D nanoplasmonic eutectic composite that exhibits localized surface plasmon resonance at 595 nm. This eutectic composite is produced by directional solidification with the micro‐pulling‐down method and consists of a 3D, multiscale network of silver, nanometer‐thick, micron‐long sheets, and triangular cross‐section microprecipitates embedded in a crystalline bismuth oxide matrix. Annealing at 600 °C further refined the structure and introduced metallic nanoparticles that exhibited plasmonic resonance in the optical region of the spectrum. This is the first demonstration of plasmonic behavior in a eutectic‐based composite, which is engineered specifically for this purpose using a self‐organization mechanism.

Photoluminescence (PL) of porous silicon (pSi) prepared from Czochralski silicon (Cz-Si) annealed up to 1620 K at enhanced pressure of argon up to 1 GPa (HP-HT treatment) was investigated. The intensity of PL with maximum at 680±720 nm decreases with the pressure for pSi prepared from the substrates treated at 1400 K, and increases with the pressure for pSi prepared from the substrates treated at 1620 K. The pSi films prepared from the HP-HT treated substrates were relaxed, contrary to those on the substrates annealed at 1620 K for 30 min at 10 5 Pa. Although our results revealed that photoluminescence properties of pSi depend significantly on the presence of defects created during the oxygen precipitation process, the role of other defects such as non-radiative recombination centres and metallic contamination should be still under consideration.

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. This paper reports the development of a bulk nanoplasmonic, Bi2O3-Ag eutectic-based metamaterial with a tunable plasmonic resonance between orange and green wavelengths. The material, obtained by a simple growth technique, exhibits a silver nanoparticle-related localized surface plasmon resonance (LSPR) in the visible wavelength range. We demonstrate the tunability of the LSPR (spectral position, width and intensity) as a function of the annealing temperature, time and the atmosphere. The critical role of the annealing atmosphere is underlined, annealing in vacuum being the most effective option for a broad control of the LSPR. The various potential mechanisms responsible for tuning the localized surface plasmon resonance upon annealing are discussed in relation to the nanostructures of the obtained materials.

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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. The nanocomposites are made of a sodium-boron-phosphate glass matrix doped with silver nanoparticles (nAg) or co-doped with nAg and Er3+ ions by NanoParticle Direct Doping method. We further show that the different origins of the two types of defect-related luminescence behaviour are attributable to either a metal-glass defect (MG1) or a metal-glass-rare-earth ion defect (MGR1). Such materials could potentially be used for data writing and erasing using laser illumination with a ‘tight’ focus such as direct laser writing.

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