Er(3+) doped phosphoniobate glasses and planar waveguides: structural and optical properties

Phosphoniobate glasses with composition (mol%) (100-x) NaPO(3)-xNb(2)O(5) ( x varying from 11 to 33) were prepared and characterized by means of thermal analysis, Fourier transform infrared spectroscopy, Raman scattering and (31)P nuclear magnetic resonance. The addition of Nb(2)O(5) to the polyphosphate base glass leads to depolymerization of the metaphosphate structure. Different colors were observed and assigned as indicating the presence of Nb(4+) ions, as confirmed by electron paramagnetic resonance measurements. The color was observed to depend on the glass composition and melting temperature as well. Er(3+) containing samples were also prepared. Strong emission in the 1550 nm region was observed. The Er(3+4)I(15/2) emission quantum efficiency was observed to be 90% and the quenching concentration was observed to be 1.1 mol%( 1.45 x 10(20) ions cm(-3)). Planar waveguides were prepared by Na(+)-K(+)-Ag(+) ion exchange with Er(3+) containing samples. Optical parameters of the waveguides were measured at 632.8, 543.5 and 1550 nm by the prism coupling technique as a function of the ion exchange time and Ag(+) concentration. The optimized planar waveguides show a diffusion depth of 5.9 mu m and one propagating mode at 1550 nm.

Optical, electrical, and thermochromic properties of polyazothiophene Langmuir-Blodgett films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nonlinear optical properties of antimony-germanium-sulfur glasses at 1560 nm

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structure and optical properties of [Ba1-xY2x/3](Zr0.25Ti0.75)O-3 powders

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On-line redox speciation analysis of antimony using L-proline immobilized on controlled pore glass and hydride generation inductively coupled plasma optical emission spectrometry for detection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Optical chemical sensors using polythiophene derivatives as active layer for detection of volatile organic compounds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

(Sr,Tm)ZrO3 powders prepared by the polymeric precursor method: Synthesis, optical properties and morphological characteristics

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Formation of beta-nickel hydroxide plate-like structures under mild conditions and their optical properties

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of Different Methods of Optical Impression Making on the Marginal Gap of Onlays Created with CEREC 3D

Objectives: This study evaluated the marginal gaps on several surfaces of onlays created with the Cerec 3D system using one intraoral and two extraoral optical impression methods. Methods: A human molar (#19) was mounted with its adjacent teeth on a typodont (Frasaco) and prepared for a MODL onlay. The typodont was assembled in the mannequin head in order to simulate clinical conditions. The same operator took 36 individual optical impressions using a CEREC 3D camera. For group 1 (IP), a thin layer of titanium dioxide powder (CEREC powder-VITA) was applied directly onto the surface of the preparation for imaging (n=12). For group 2 (EP), a sectional impression was taken with hydrocolloid Identic Syringable (Dux Dental), a die made with polyvinylsiloxane KwikkModel Scan (R-dental Dentalerzeugnisse GmbH) and powdered with titanium dioxide for imaging (n=12). For group 3 (ES), a sectional impression was taken with PVS and a sectional stock tray, a die fabricated in stone (Diamond die- HI-TEC Dental Products) and the die being imaged without powdering (n=12). One operator designed and machined the onlays in Vita Blocks Mark II for Cerec (VITA) using a CEREC 3D. The marginal gaps (pm) were measured with an optical microscope (50x) at 12 points, three on each surface of the MODL. The results were analyzed by two-way ANOVA/Tukey's (p=0.05). Results: The overall mean marginal gaps (mu m) for the three methods were: IP=111.6 (+/- 34.0); EP=161.4 (+/- 37.6) and ES=116.8 (+/- 42.3). IP and ES were equal, but both were significantly less than EP. The pooled mean marginal gaps (mu m) for the occlusal = 110.5 (+/- 39) and lingual = 111.5 (+/- 30.5) surfaces were equivalent and significantly less than the distal = 136.5 (+/- 42.5) and mesial = 161.1 (+/- 43.3). Conclusion: The marginal gap of CEREC 3D onlay restorations was not different when the optical impression was taken intraorally vs extraorally using a stone cast that does not require powdering. The lingual and occlusal surfaces showed the lowest gaps.

Structural refinement, optical and microwave dielectric properties of BaZrO3

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of different solvents on the structural, optical and morphological properties of CdS nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoluminescence in quasi-amorphous Pb0.8X0.2Zr0.53Ti0.47O3 (X = Ca, Sr and Ba) powders: An optical and structural study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Optical and dielectric relaxor behaviour of Ba(Zr0.25Ti0.75)O-3 ceramic explained by means of distorted clusters

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Optical spectroscopy and upconversion luminescence in Nd3+ doped Ga10Ge25S65 glass

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Strong infrared spectral broadening in low-loss As-S chalcogenide suspended core microstructured optical fibers

We report the fabrication and characterization of the first guiding chalcogenide As(2)S(3) microstructured optical fibers (MOFs) with a suspended core. At 1.55 mu m, the measured losses are approximately 0.7 dB/m or 0.35 dB/m according to the MOF core size. The fibers have been designed to present a zero dispersion wavelength (ZDW) around 2 mu m. By pumping the fibers at 1.55 mu m, strong spectral broadenings are obtained in both 1.8 and 45-m-long fibers by using a picosecond fiber laser. (C) 2010 Optical Society of America