Navegação IPEN por Autores IPEN "DIPOLD, JESSICA"

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  • IPEN-DOC 29785

    DIPOLD, JESSICA ; BORDON, CAMILA D.S.; MAGALHAES, EVELLYN S.; KASSAB, LUCIANA R.P.; JIMENEZ-VILLAR, ERNESTO; WETTER, NIKLAUS U. . 1337 nm emission of a Nd3+-doped TZA glass random laser. Nanomaterials, v. 13, n. 13, p. 1-11, 2023. DOI: 10.3390/nano13131972

    Abstract: Random lasers have been studied using many materials, but only a couple have used glass matrices. Here, we present a study of zinc tellurite and aluminum oxide doped with different percentages of neodymium oxide (4 wt.%, 8 wt.%, and 16 wt.%) and demonstrate for the first time random laser action at 1337 nm. Laser emission was verified and the laser pulse’s rise time and input–output power slope were obtained. A cavity composed of the sample’s pump surface and an effective mirror formed by a second, parallel layer at the gain-loss boundary was probably the main lasing mechanism of this random laser system. The reason for the absence of emission at 1064 nm is thought to be a measured temperature rise in the samples’ active volume.

    Palavras-Chave: doped materials; laser materials; neodymium lasers; scattering; glass; tellurium oxides

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  • IPEN-DOC 30047

    BERECZKI, ALLAN ; DIPOLD, JESSICA ; FREITAS, ANDERSON Z. ; WETTER, NIKLAUS . Direct nanoplastics detection below the diffraction limit using micro Raman. In: CONFERENCE ON LASERS AND ELECTRO-OPTICS: APPLICATIONS AND TECHNOLOGY, May 7-12, 2023, San Jose, CA, USA. Proceedings... Washington, DC, USA: Optica Publishing Group, 2023. DOI: 10.1364/CLEO_AT.2023.ATh3I.2

    Abstract: Raman spectra of polystyrene nanoparticles of 50 nm diameter were directly measured using micro-Raman spectroscopy. Data analysis demonstrated that particles as small as 20 nm could be directly measured with this simple and robust technique.

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  • IPEN-DOC 29619

    BORDON, CAMILA D. da S.; DIPOLD, JESSICA ; WETTER, NIKLAUS U. ; ROSSI, WAGNER de ; FREITAS, ANDERSON Z. ; KASSAB, LUCIANA R.P.. Effect of silver nanoparticles on the optical properties of double line waveguides written by fs laser in Nd3+-doped GeO2-PbO glasses. Nanomaterials, v. 13, n. 4, p. 1-13, 2023. DOI: 10.3390/nano13040743

    Abstract: Nd3+-doped GeO2-PbO glass with silver (Ag) nanoparticles (NPs) are produced with double line waveguides through fs laser processing for photonic applications. A Ti:sapphire fs laser at 800 nm was used to write the waveguides directly into the glass 0.7 mm beneath the surface. This platform is based on pairs of parallel lines with spacing of 10 µm, each pair being formed by two identical written lines but in two different configurations of 4 or 8 separately processed lines, which are coincident. The results of optical microscopy, absorbance measurements, refractive index change, beam quality factor (at 632 and 1064 nm), photoluminescence, propagation losses, and relative gain at 1064 nm are presented. The structural changes in the glass due to the presence of Ag NPs were investigated by Raman spectroscopy. At 632 and 1064 nm, x,y-symmetrical guiding was observed, and for both kinds of overlapping pulses, a refractive index alteration of 10−3 was found in both directions. Photoluminescence growth of ~47% at 1064 nm was observed due to the plasmonic effect of Ag NPs. In dual waveguides containing Ag NPs, the relative gain obtained increased by 40% and 30% for four and eight overlapping lines, respectively, at 600 mW of 808 nm pump power, when compared to waveguides without those metallic NPs. We highlight the resultant positive internal gains of 5.11 and 7.12 dB/cm that showed a growth of ~40% and ~30%, respectively, with respect to the samples without Ag NPs. The increase in photoluminescence and relative gain were related to the local field growth produced by Ag NPs. The present results show that the addition of Ag NPs impacts positively on the optical performance at 1064 nm of double line waveguides processed by fs laser writing in Nd3+-doped GeO2-PbO glass, opening news perspectives for photonics.

    Palavras-Chave: lasers; pulses; germanates; waveguides; optical equipment; silver; nanoparticles

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  • IPEN-DOC 29356

    BORDON, CAMILA D.S.; DIPOLD, JESSICA ; BARRETO, LUIZ M.M.; WETTER, NIKLAUS U. ; ROSSI, WAGNER de ; KASSAB, LUCIANA R.P.. Effect of silver nanoparticles on the production of double line waveguide written by fs laser on Nd3+ doped GeO2-PbO glasses. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, August 7-11, 2022, Recife, PE. Proceedings... Washington, DC, USA: Optica Publishing Group, 2022. DOI: 10.1364/LAOP.2022.Tu4A.41

    Abstract: We report the production of double waveguides in Ge2O-PbO glasses doped with Nd3+ and silver nanoparticles by direct femtosecond laser writing. The beam quality measurements and refractive index change are presented.

    Palavras-Chave: lasers; pulses; germanates; waveguides; optical equipment; silver; nanoparticles

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  • IPEN-DOC 28756

    DIPOLD, JESSICA ; MAGALHAES, EVELLYN S.; BORDON, CAMILA D.S.; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U. . Emission properties study of a Nd3+ doped TZA glass random laser. In: JIANG, SHIBIN (Ed.); DIGONNET, MICHEL J.F. (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, January 22 - February 28, 2022, San Francisco, CA, USA. Proceedings... Bellingham, WA, USA: SPIE, 2022. p. 119970I-1 - 119970I-6. (Proceedings SPIE 11997, Optical Components and Materials XIX). DOI: 10.1117/12.2610107

    Abstract: Random lasers (RLs) have been thoroughly studied for applications such as high definition speckle free imaging, lithography, miniature spectroscopy, etc. RLs made with crystalline powders have shown promising results, with high emission efficiencies and narrow wavelength bandwidth. However, few studies on glass random lasers have been made, since its inhomogeneous broadening make it hard to verify the linewidth narrowing characteristic of laser emission. Here, we describe linewidth and temporal measurements for a TZA glass doped with 16 wt% neodymium. We verified a 0.5 nm linewidth narrowing at laser threshold. The pump intensity where the transition occurs coincided with the appearance of a faster emission decay, showing the presence of laser emission for higher pump power energies. This result is promising in understanding random lasing for glass powders.

    Palavras-Chave: lasers; randomness; neodymium ions; glass; doped materials; rare earths

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  • IPEN-DOC 29319

    WETTER, NIKLAUS ; FREITAS, ANDERSON Z. ; BERECZKI, ALLAN ; PASCOAL, DIEGO R.C. ; DIPOLD, JESSICA ; PARRA, DUCLERC ; ROSSI, WAGNER ; CABRAL, FERNANDA V. ; RIBEIRO, MARTHA S. . From micro to nano Raman: new developments in the detection of micro and nanoplastics of marine origin from the Amazon basin to Santos. In: ENCONTRO BRASILEIRO DE ESPECTROSCOPIA RAMAN, 7., 5-8 de dezembro, 2022, São Pedro, SP. Resumo... 2022.

    Abstract: The environmental accumulation of nanoplastics formed by material of anthropic origin has raised doubts about their safety, especially to the human body. While microplastics are accidentally consumed, nanoplastics (NPs) are even more concerning as they are much more likely to be absorbed by human body cells. It is known that plastics smaller than 200 nm can penetrate cell membranes and cross the blood-brain barrier. Studies have shown that polystyrene (PS) NPs from the environment carry a high load of toxins capable of compromising human brain cells. Very little is still known about what effects, cytotoxic or not, these plastics have on different organs. Understanding the property-function relationship of nanoparticles in various fields of application involves determining their physicochemical properties, which is still a formidable challenge to date. Our project focuses on the development of a methodology for the detection of micro- and NPs using micro-Raman, TERS (Tip Enhanced Raman Spectroscopy), collinear Raman and AFM, nuclear techniques, as well as a methodology for in vitro evaluation of the toxic effects of these materials through biochemical assays of cytotoxicity and genotoxicity. The project contemplates the determination of the adsorption capacity of metallic ions by NPs and the absorption of micro- and nanoplastics in cell cultures with radioactive tracers, the determination of microplastics in tissues from necropsies of marine animals and gamma spectroscopy of the cellular incorporation of NPs labeled with radioactive isotopes. In figure 1 we show examples of (a) the detection of microplastics from the Santos basin and comparison to Raman reference database (KnowItAll®), (b) detection of NPs in mouse fibroblast cells and (c) detection of very small particles (50 nm) which can be achieved by co-localized techniques of AFM + Raman using special, narrow (50 m), femtosecond laser written gratings on quartz.

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  • IPEN-DOC 29317

    BORDON, CAMILA D.S.; DIPOLD, JESSICA ; ROSSI, WAGNER de ; FREITAS, ANDERSON Z. ; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U. . Influence of Ag nanoparticles in waveguides on doped germanate glasses. In: ENCONTRO BRASILEIRO DE ESPECTROSCOPIA RAMAN, 7., 5-8 de dezembro, 2022, São Pedro, SP. Resumo... 2022.

    Abstract: Writing by using femtossecond (fs) laser enables fast prototyping and has low complexity compared to other fabrication methods. For materials that do not allow light confinement and propagation, waveguiding by double-line technology is necessary. Previously, we demonstrated waveguiding in double-lines for undoped germanate and tellurite glasses, as well as GeO2-PbO doped with Er3+/Yb3+ and Nd3+. The results for the Nd3+ glass were promising for the fabrication of integrated amplifiers, lossless components and lasers. This motivated the present investigation, where silver (Ag) nanoparticles (NPs) were added to the Nd3+ doped GeO2-PbO bulk in order to enhance its guiding capabilities. Raman measurements were made with a LabRam HR Evolution - HORIBA, using a 532 nm laser with 100 mW power and a 10 x objective lens with 0.25 NA. An integration time of 1 second and 15 accumulations was used to reduce noise and make the observed peaks clearer. First, the Raman spectrum was measured for the bulk (b) glass (Fig. 1a) and between the written lines (Fig. 1a). There are no substantial changes between these, indicating, as expected, that there are no relevant structural changes in the guiding region between the two lines. However, comparing the bulk region (Fig. 1a) with the inside of the written line with 4 superimposed lines (Fig. 1b), there are major changes in some of the peaks. The peak at 411.2 cm-1 (b) shifted to 433.9 cm-1, indicating modification in the symmetric stretching vibrations of the Ge-O-Ge bonds. The peak at 517.5 cm-1 (b) to 508.1 cm-1 shows changes in the symmetric stretching vibrations along the Ge- O-Ge chain, demonstrating lower density of these bonds in the irradiated region. A slight change of the 782.3 cm-1 and 867.4 cm-1 (b) are also verified, and are related to the Ge-O- and Ge-O-Ge symmetric stretching vibrations in the GeO4 tetrahedral units and asymmetric stretching vibrations of the Ge-O-Ge bonds, respectively. These changes are larger than the ones previously shown for the same material without the Ag NPs, which shows the influence of the nanoparticles during the writing process.

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  • IPEN-DOC 28558

    PELOSI, ANDRE G.; SANTOS, SABRINA N.C. dos; DIPOLD, JESSICA ; ANDRADE, MARCELO B. de; HERNANDES, ANTONIO C.; ALMEIDA, JULIANA M.P. de; MENDONCA, CLEBER R.. Investigation of the influence of transition metal ions in niobium-borotellurite glasses through vibrational and nonlinear optical spectroscopy. In: BRAZIL MRS MEETING, 19th; INTERNATIONAL UNION OF MATERIALS RESEARCH SOCIETIES - INTERNATIONAL CONFERENCE ON ELECTRONIC MATERIALS, August 30 - September 3, 2021, Online. Abstract... São Carlos, SP: Aptor Software, 2021. p. 176-176.

    Abstract: Tellurite glasses are know as good candidates to photonic devices’ production because they exhibit third-order nonlinear optical susceptibilities larger than conventional silicate and borate glasses. In addition, for glass materials such nonlinearity can be increased by adding transition or heavy metal ions. In this direction, this work analyzed the influence of Ta5+ and Zr2+ on the physical, structures, and nonlinear optical properties of niobium-borotellurite (TBN) glasses. The samples were synthesized by the melt-quench technique using a melting temperature of around 1000 ºC. DSC measurements were performed to obtain the glass transition temperature. The densities were determined by the Archimedes method. To analyze the local structure of the samples FTIR and Raman spectroscopies were used . The spectrum of nonlinear refractive index (n2) for the TBN glass doped with Ta5+ and Zr2+ ions was measured using the tunable femtosecond Z-scan technique [1]. Such results were compared with the BGO model, which involves empirical relations between the linear and nonlinear refractive index. The addition of metal transition ions did not lead to meaningful changes in the glass transition temperatures (Tg). The formation of non-bridging oxygen and BO3 units was observed from the structural analysis. The n2 value determined indicates that the nonlinear optical responses are associated with the glass matrix. The structural changes caused by the addition of Ta5+ and Zr2+ demonstrated a decrease followed by an increase in the value of the molar electronic polarization of the samples, respectively.

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  • IPEN-DOC 29349

    JIMENEZ-VILLAR, ERNESTO ; WETTER, NIKLAUS U. ; DIPOLD, JESSICA ; MARQUES, FRANCISCO C.. Localization of light: a power sensing tool. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, August 7-11, 2022, Recife, PE. Proceedings... Washington, DC, USA: Optica Publishing Group, 2022. DOI: 10.1364/LAOP.2022.Th1A.7

    Abstract: Localization of light induced by correlation in the scatterers’ positions is achieved in an ordered photonic colloidal (TiO2@Silica) suspension. A strongly enhanced light-matter coupling is observed as the concentration of TiO2@Silica is increased above threshold.

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  • IPEN-DOC 29320

    BERECZKI, ALLAN ; PASCOAL, DIEGO R.C. ; DIPOLD, JESSICA ; GIMILIANI, GIOVANA T. ; PARRA, DUCLERC F. ; FREITAS, ANDERSON Z. ; WETTER, NIKLAUS . Micro-Raman spectroscopy for identification of microplastics in the São Vicente estuarine. In: ENCONTRO BRASILEIRO DE ESPECTROSCOPIA RAMAN, 7., 5-8 de dezembro, 2022, São Pedro, SP. Resumo... 2022.

    Abstract: Microplastics (MPs) are a concern regarding our environment due to the risks posed by the interactions of the large amounts of anthropogenic MPs dumped in the environment with biological systems. MPs have been vastly found in the environment and are transferred to the food chain with MPs being detected in foods, beverages and even in human blood and breastmilk. Understanding the behavior and characteristics of MPs is critical to assessing potential health risks (human and environmental) related to MPs and taking steps to prevent them from entering the ecosystem. Micro Raman spectroscopy is a powerful tool for measuring and characterizing MPs particles, being considered the gold standard because it allows identification of both the polymer matrix and possible pigments and contaminants. Furthermore it offers the possibility of characterizing both the chemical structure as well as the morphological features of the MPs. We utilized a Raman system to characterize MPs from the environment. Results from a standard MP sample were successfully measured and identified to reference spectra and even small portions of the sample as small as a few μm are suitable for obtaining a high quality spectrum for identification of the material (Fig1). Samples collected from at the São Vicente estuarine are being studied and by means of comparison with the Willey database it was possible to identify MP, additives and contaminants, thus demonstrating the power of the technique.

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  • IPEN-DOC 28855

    BORDON, CAMILA D.S.; DIPOLD, JESSICA ; FREITAS, ANDERSON Z. ; WETTER, NIKLAUS U. ; ROSSI, WAGNER de ; KASSAB, LUCIANA R.P.. A new double-line waveguide architecture for photonic applications using fs laser writing in Nd3+ doped GeO2-PbO glasses. Optical Materials, v. 129, p. 1-6, 2022. DOI: 10.1016/j.optmat.2022.112495

    Abstract: A new double-line waveguide architecture produced in Nd3+ doped GeO2-PbO glasses is presented for photonic applications. The waveguides are written directly into Nd3+ doped GeO2-PbO glasses using a Ti:Sapphire femtosecond (fs) laser, operating at 800 nm, delivering 30 fs pulses at 10 kHz repetition rate and writing speed of 0.5 mm/s. Two parallel lines form a dual-waveguide each line being a result of either 4 or 8 superimposed lines. Results of propagation losses, M2 beam quality factor at 632 and 1064 nm, refractive index change, and relative gain at the signal wavelength (1064 nm) are presented. Structural changes, due to laser writing process were investigated by Raman spectroscopy. The observed near-field pattern image showed good waveguiding quality, consisting of a single, circular lobe. X,y-symmetrical guiding for both waveguides was observed. The relative gain reached 4.5 and 6.0 dB/cm for 4 and 8 superimposed lines, respectively, for 420 mW of 808 nm pumping. Propagation losses were 0.89 and 0.44 dB/cm, for 4 and 8 superimposed lines, respectively, leading to positive internal gain of 3.6 and 5.56 dB/cm. The results obtained in the present work demonstrate that this new double line architecture for Nd3+ doped GeO2-PbO glasses is promising for the fabrication of integrated amplifiers, lossless components and lasers.

    Palavras-Chave: germanates; glass; lasers; waveguides; optical properties

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  • IPEN-DOC 27334

    DIPOLD, JESSICA ; SILVA, DANILO A.A. da ; BERECZKI, ALLAN ; JIMENEZ-VILLAR, E. ; WETTER, NIKLAUS U. . Polydispersed Nd3+:YVO4+SiO2 powders for highly efficient random lasers. In: JIANG, SHIBIN (Ed.); DIGONNET, MICHEL J.F. (Ed.) SPIE PHOTONICS WEST; SPIE OPTO, February 1-6, 2020, San Francisco, USA. Proceedings... Washington, USA: SPIE, 2020. p. 112760N-1 - 112760N-8. (Proceedings SPIE 11276, Optical Components andMaterials XVII). DOI: 10.1117/12.2545028

    Abstract: Random lasers are cheap and easy to fabricate, having several different applications such as early cancer detection, encryption and Speckle-free imaging. However, few fabricated random lasers present high efficiency, which limits their possible applications. In a recent work, our group achieved a record efficiency by developing random lasers that use compacted, polydispersed yttrium vanadate doped with neodymium (Nd3+:YVO4 ) powders to create separate regions for gain and light diffusion. Large particles are responsible for the light diffusion, while the small particles that occupy the spaces between them create gain pockets, absorbing the pumped light. In this work, this strategy is refined by using passive particles (SiO2) for light diffusion, restricting the laser active particles to the gain pockets. The first attempt with this strategy used 30% of Nd3+:YVO4 small powders and 70% of large SiO2 particles. Without any further optimization, the result achieved is already 40% of the highest obtained efficiency in the previously studied Nd3+:YVO4 polydisperse sample, showing a promising result to further improve this new strategy and reach even larger efficiencies with less laser active material.

    Palavras-Chave: randomness; lasers; optical pumping; gain; absorption

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  • IPEN-DOC 30050

    DIPOLD, JESSICA ; WETTER, NIKLAUS U. ; FREITAS, ANDERSON Z. ; MARQUES, FRANCISCO C.; DOGARIU, ARISTIDE; JIMENEZ-VILLAR, ERNESTO . Raman enhancement induced by localization of light (TiO2@Silica plus silica nanoparticles). In: CONFERENCE ON LASERS AND ELECTRO-OPTICS: FUNDAMENTAL SCIENCE, May 7-12, 2023, San Jose, CA, USA. Proceedings... Washington, DC, USA: Optica Publishing Group, 2023. DOI: 10.1364/CLEO_FS.2023.FTh1B.7

    Abstract: Strong enhancement of the Raman signal is observed in ethanol suspension of TiO2@Silica, being stronger as the TiO2@Silica filling fraction is increased above threshold, and when silica nanoparticles are added.

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  • IPEN-DOC 29353

    DIPOLD, JESSICA ; BERECZKI, ALLAN ; PINHEIRO, GUSTAVO; VASCONCELOS, KAMILLA; FREITAS, ANDERSON Z. de ; WETTER, NIKLAUS U. . Raman Spectroscopy of irradiated and non-irradiated plastics. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, August 7-11, 2022, Recife, PE. Proceedings... Washington, DC, USA: Optica Publishing Group, 2022. DOI: 10.1364/LAOP.2022.Tu4A.10

    Abstract: Understanding radiation damage to plastic is of great interest for possible construction applications. Two different plastics were gamma irradiated and their property changes were studied with micro-Raman spectroscopy, showing promising results in increasing its toughness.

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  • IPEN-DOC 30185

    DIPOLD, JESSICA ; BORDON, CAMILA D.S.; MAGALHAES, EVELLYN S.; KASSAB, LUCIANA R.P.; JIMENEZ-VILLAR, ERNESTO; WETTER, NIKLAUS U. . Random laser emission in Nd3+ doped tellurite glass. In: INTERNATIONAL CONFERENCE ON OPTICAL MEMS AND NANOPHOTONICS; SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, July 31 - August 3, 2023, Campinas, SP. Proceedings... Piscataway, NJ, USA: IEEE, 2023. DOI: 10.1109/OMN/SBFOTONIOPC58971.2023.10230929

    Abstract: Random lasers are easier and cheaper to manufacture than regular ones, being made of several materials such as polymers, powders or dyes. Glass random lasers have been rarely studied due to their inhomogeneous broadened emission and low damage threshold. Here, we study Nd 3 +doped Te0 2 -ZnO-Al 2 0 3 glasses with different concentrations of rare-earth doping (4 wt.%, 8 wt.% and 16 wt.%). Emission intensity per pump fluence and fluorescence decay time measurements showed the potential of these glasses for random laser applications in the near-infrared region.

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  • IPEN-DOC 29361

    JIMENEZ-VILLAR, ERNESTO ; GOMES, ANDERSON A.V.; WETTER, NIKLAUS U. ; DIPOLD, JESSICA ; MESTRE, VALDECI; DOMINGUEZ, CHRISTIAN T.. Random laser in ordered colloidal suspensions. In: LATIN AMERICA OPTICS AND PHOTONICS CONFERENCE, August 7-11, 2022, Recife, PE. Proceedings... Washington, DC, USA: Optica Publishing Group, 2022. DOI: 10.1364/LAOP.2022.W1B.2

    Abstract: Random lasing is achieved in an ordered photonic colloidal (TiO2@Silica) suspension. Stronger correlation in the scatterers’ (TiO2@Silica) position, induced by stronger and longer-range Coulomb interaction improves light localization and random laser performance.

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  • IPEN-DOC 30193

    WETTER, NIKLAUS U. ; VIEIRA, RENATO J.R. ; SILVA, DANILO M. da ; JORGE, KELLY C. ; JIMENEZ-VILLAR, ERNESTO ; GIEHL, JULIA M. ; MIRANDA, ADRIANA R. de ; DIPOLD, JESSICA . Random lasers: review of research activities at IPEN. In: INTERNATIONAL CONFERENCE ON OPTICAL MEMS AND NANOPHOTONICS; SBFOTON INTERNATIONAL OPTICS AND PHOTONICS CONFERENCE, July 31 - August 3, 2023, Campinas, SP. Proceedings... Piscataway, NJ, USA: IEEE, 2023. DOI: 10.1109/OMN/SBFotonIOPC58971.2023.10230975

    Abstract: Random lasers offer advantages such as low-cost fabrication and robustness in harsh environments and have applications in sensing, imaging, communications, and security. Our current research focuses on advanced materials, active control techniques, integration with other photonic structures, and exploration of Anderson localization and polydisperse effects. Coherent feedback in cavity-enhanced random lasers is discussed as means to achieve specific emission characteristics, and emission at 1300 nm is shown for the first time.

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  • IPEN-DOC 28139

    DOMINGUEZ, CHRISTIAN T.; GOMES, ANDERSON A.V.; WETTER, NIKLAUS U. ; DIPOLD, JESSICA ; MESTRE, VALDECI; MARTINS, WELITON S.; JIMENEZ-VILLAR, ERNESTO. Random lasing at localization induced in correlated colloidal system. Optical Materials, v. 120, p. 1-7, 2021. DOI: 10.1016/j.optmat.2021.111428

    Abstract: Random lasers have the potential for cheap and coherent light sources which, in the particular case of colloidal suspensions, are completely flexible and can take on any desired shape. Here, we studied random lasing in correlated colloidal systems composed by TiO2@Silica nanoparticles suspended in ethanol solutions of Rhodamine 6G. TiO2 particles with two different silica layers (thicknesses of 40 nm and 70 nm) were prepared. The Random laser performance improves when the silica shell is thicker (70 nm), which was attributed to a stronger localization of light (higher density of localized states) induced by stronger correlation in the scatterers' (TiO2@Silica) position as a consequence of a stronger and longer-range Coulomb interaction between the scatterers. Light diffraction patterns in both TiO2@Silica suspensions showed a stronger correlation in the scatterers’ position, being stronger when the silica shell is thicker.

    Palavras-Chave: randomness; lasers; scattering; correlations; colloids

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  • IPEN-DOC 29716

    AMARO, AUGUSTO A.; MATTOS, GUILHERME R. da S.; NISHIMURA, MARCOS V. de M.; DIPOLD, JESSICA ; WETTER, NIKLAUS U. ; KASSAB, LUCIANA R.P.. Silver nanoclusters tunable visible emission and energy transfer to Yb3+ Ions in co-doped GeO2-PbO glasses for photonic applications. Nanomaterials, v. 13, n. 7, p. 1-15, 2023. DOI: 10.3390/nano13071177

    Abstract: This work investigates the optical properties of Yb3+ ions doped GeO2 -PbO glasses containing Ag nanoclusters (NCs), produced by the melt-quenching technique. The lack in the literature regarding the energy transfer (ET) between these species in these glasses motivated the present work. Tunable visible emission occurs from blue to orange depending on the Yb3+ concentration which affects the size of the Ag NCs, as observed by transmission electron microscopy. The ET mechanism from Ag NCs to Yb3+ ions (2F7/2 → 2F5/2) was attributed to the S1→T1 decay (spin-forbidden electronic transition between singlet–triplet states) and was corroborated by fast and slow lifetime decrease (at 550 nm) of Ag NCs and photoluminescence (PL) growth at 980 nm, for excitations at 355 and 405 nm. The sample with the highest Yb3+ concentration exhibits the highest PL growth under 355 nm excitation, whereas at 410 nm it is the sample with the lowest concentration. The restriction of Yb3+ ions to the growth of NCs is responsible for these effects. Thus, higher Yb3+ concentration forms smaller Ag NCs, whose excitation at 355 nm leads to more efficient ET to Yb3+ ions compared to 410 nm. These findings have potential applications in the visible to near-infrared regions, such as tunable CW laser sources and photovoltaic devices.

    Palavras-Chave: ytterbium ions; silver; nanomaterials; germanates; glass; photoluminescence

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  • IPEN-DOC 28579

    VECCHIA, MARIA E.K.D. ; ZAINE, MARIANA A. ; KOMATSU, LUIZ G.H. ; DIPOLD, JESSICA ; FREITAS, ANDERSON Z. ; WETTER, NIKLAUS ; PARRA, DUCLERC F. . Study of the incorporation of TiO2/Ag nanoparticles in polyamide by casting method aiming for biocide application. In: CONGRESSO BRASILEIRO DE POLÍMEROS, 16., 24-28 de outubro, 2021, Ouro Preto, MG. Anais... São Carlos, SP: Aptor Software, 2021. p. 789-793.

    Abstract: This study consists in the characterization of polyamide (PA6) films charged with different concentrations of silver nanoparticles deposited in titanium dioxide (TiO2) carrier. The silver nanoparticles were synthesized according to the method adapted from Turkevich using a titanium dioxide carrier and inserted, by suspension, in a polyamide solution. The preparation of PA: AgNp films was performed by the casting method by the dissolution of PA pellets in formic acid. The analysis and characterization of the films by the XRD, DSC, TGA and Raman confocal techniques indicated incorporation of nanoparticles into the polymers, a second thermogravimetric decomposition event as the concentration of AgNp-TiO2 increased and there was no significant change in crystallinity.

    Palavras-Chave: nanoparticles; polyamides; nanostructures; silver; titanium oxides

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Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

✔ 95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, bibl@ipen.br .

✔ Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

✔ O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

✔ Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

✔ Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.


2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.