Search results for "Optical limiting"

showing 3 items of 3 documents

Synthesis and physico-chemical characterization of Au/TiO2 nanostructures formed by novel "cold" and "hot" nanosoldering of Au and TiO2 nanoparticles…

2011

Abstract A novel approach to synthesize Au/TiO2 nanostructures with interesting optical properties is presented and discussed. It is based on the nanoparticle “cold” or “hot” nanosoldering occurring when two water suspensions of Au and TiO2 nanoparticles are merely mixed at room temperature or laser irradiated after mixing. Thanks to the high fraction and mutual reactivity of surface species, immediately after the mixing process, the encounters between Au and TiO2 nanoparticles in liquid phase are enough for “cold” nanosoldering of gold nanoparticles onto TiO2 nanoparticles to occur. The optical characterizations show that this fast process (timescale less than 1 min) is followed by a slowe…

Materials scienceNanostructureNanoparticleNanotechnologyLaserTitanium oxidelaw.inventionColloid and Surface ChemistryUltraviolet visible spectroscopyChemical engineeringColloidal goldlawGold Titanium oxide Nanoparticles Optical limiting properties UV–vis TEM FluorescenceIrradiationRefractive indexSettore CHIM/02 - Chimica Fisica
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Sensitization of nanocrystalline TiO2 with 3,4,9,10-perylene tetracarboxylic acid

2014

Optical properties of 3,4,9,10-perylene tetracarboxylic acid (PTCA) in the presence of nanocrystalline TiO2 (nominal diameter 15 nm) have been investigated in ethanol solution and in the solid state by UV-Vis absorption spectroscopy and steady-state and time-resolved fluorescence. Experimental results show that, in ethanol, the presence of TiO2 nanoparticles causes significant changes in the typical absorption and fluorescence bands of PTCA and in the fluorescence relaxation time. Similar effects are also detected in solid samples, obtained by electrospray deposition technique. The nonlinear optical properties of the PTCA-TiO2 in ethanol solutions were investigated using the single-beam Z-s…

ElectrosprayMaterials scienceAbsorption spectroscopyAnalytical chemistryBioengineeringchemistry.chemical_compoundGeneral Materials ScienceTitania nanoparticles Dye sensitization Absorption and fluorescence spectroscopies Optical limiting Z-scan methodDeposition (law)Settore CHIM/02 - Chimica FisicaZ-scan methodTitania nanoparticles; Dye sensitization; Absorption and fluorescence spectroscopies; Optical limiting; Z-scan methodDye sensitizationGeneral ChemistryCondensed Matter PhysicsFluorescenceAtomic and Molecular Physics and OpticsNanocrystalline materialchemistryModeling and SimulationAbsorption (chemistry)Optical limitingLuminescenceTitania nanoparticlesPeryleneAbsorption and fluorescence spectroscopiesJournal of Nanoparticle Research
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Opto-thermal dynamics of thin-film optical limiters based on the VO2 phase transition

2022

Protection of human eyes or sensitive detectors from high-intensity laser radiation is an important challenge in modern light technologies. Metasurfaces have proved to be valuable tools for such light control, but the actual possibility of merging multiple materials in the nanofabrication process hinders their application. Here we propose and numerically investigate the opto-thermal properties of plane multilayered structures with phase-change materials for optical limiters. Our structure relies on thin-film VO2 phase change material on top of a gold film and a sapphire substrate. We show how such a multi-layer structure can act as a self-activating device that exploits light-to-heat conver…

VO2photonicsoptical limitingSettore ING-INF/02 - Campi ElettromagneticiElectronic Optical and Magnetic Materials
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