Search results for "wave"

A damping preconditioner for time-harmonic wave equations in fluid and elastic material

2009

A physical damping is considered as a preconditioning technique for acoustic and elastic wave scattering. The earlier preconditioners for the Helmholtz equation are generalized for elastic materials and three-dimensional domains. An algebraic multigrid method is used in approximating the inverse of damped operators. Several numerical experiments demonstrate the behavior of the method in complicated two-dimensional and three-dimensional domains. peerReviewed

Caracterización de barita cubana y su reducción carbotérmica en horno de microondas

2007

The Cuban Barite (BaSO4) is characterized by X ray diffraction, chemical analysis and scanning electron microscopy. The principal components are identified and its characteristic morphology is shown. Its carbothermic reduction under microwave irradiation is carried out with the purpose of to improve the yield of this stage during the mineral transformation process in reagent of barium of diverse applications. La barita cubana (BaSO4) se ha caracterizado por difracción de rayos X, análisis químico y microscopía electrónica de barrido. Se han identificado sus componentes mayoritarios y así mismo se muestra su morfología característica. Se ha realizado su reducción carbotérmica en horno de mic…

Interactions of Ultra-cold Alkaline-earth-like and Alkali Atoms with Light

2019

This paper presents the experimental results of photoionization and photoassociation experiments performed with both ultra-cold alkaline-earth-like and alkali atoms. Photoionization cross-section was studied for 88Sr at the blue magic 390 nm wavelength as well as for 87Rb at 254 nm. We also present preliminary results of photoassociation spectroscopy of the molecular line detected near the dissociation threshold of the excited Rb*Hg molecule at D1 Rb line (795 nm).

All-Optical frequency Shifter in a Periodically Poled Lithium Tantalate Waveguide

2011

A frequency shifting device is fabricated and tested in a congruent Lithium Tantalate waveguide. Periodic poling for quasi-phase-matching and channels for operation in the near-infrared C-band were obtained, demonstrating a two-stage parametric conversion.

2017

Tailored tellurite-glasses possess excellent thermo-viscous ability and linear/nonlinear optical properties. Here, bringing together the merits of these materials with fiber optic technology, we report on the first tellurite-based core-clad dual-electrode composite fiber made by direct, homothetic preform-to-fiber thermal co-drawing. The rheological and optical properties of the selected glasses allow both to regulate the metallic melting flow and to manage the refractive index core/clad waveguide profile. We demonstrate the electrical continuity of the electrodes over meters of fiber. We believe the drawing of architectures merging electrical and optical features in a unique elongated wave…

Resonant and thermal changes of refractive index in a heavily doped erbium fiber pumped at wavelength 980 nm

2004

We report a theoretical and experimental study of the refractive index variation in a heavily doped erbium silica fiber within the spectral range 1500-1580 nm under the pumping at the wavelength 980 nm. The two main contributions in the refractive index change are addressed the resonant part determined by the saturation effect in the fiber and the thermal part stemming from the fiber heating due to the excited-state absorption and Stokes losses. We demonstrate that the thermal contribution in the resultant refractive index change is a notable value, which is the feature of erbium fibers with a high concentration of erbium ions.

Multioctave midinfrared supercontinuum generation in suspended-core chalcogenide fibers

2014

An As2S3 fiber-based supercontinuum source that covers 3500 nm, extending from near visible to the midinfrared, is successfully reported by using a 200-fs-pulsed pump with nJ-level energy at 2.5 μm. The main features of our fiber-based source are two-fold. On the one hand, a low-loss As2S3 microstructured optical fiber has been fabricated, with typical attenuation below 2 dB/m in the 1-4 μm wavelength range. On the other hand, a 20-mm-long microstructured fiber sample is sufficient to enable a spectral broadening, spreading from 0.6 to 4.1 μm in a 40 dB dynamic range.

Microstructured chalcogenide optical fibers from As2S3 glass: towards new IR broadband sources

2010

Made available in DSpace on 2013-08-28T14:12:29Z (GMT). No. of bitstreams: 1 WOS000285749500124.pdf: 1017839 bytes, checksum: f517fd8ef33fd56d66b9ccda9dc4d0f3 (MD5) Made available in DSpace on 2013-09-30T19:22:53Z (GMT). No. of bitstreams: 2 WOS000285749500124.pdf: 1017839 bytes, checksum: f517fd8ef33fd56d66b9ccda9dc4d0f3 (MD5) WOS000285749500124.pdf.txt: 33157 bytes, checksum: 1ca2ac713bf6024674249abf58520bcb (MD5) Previous issue date: 2010-12-06 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:34:00Z No. of bitstreams: 2 WOS000285749500124.pdf: 1017839 bytes, checksum: f517fd8ef33fd56d66b9ccda9dc4d0f3 (MD5) WOS000285749500124.pdf.txt: 33157 bytes,…

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

2010

Made available in DSpace on 2013-08-28T14:10:10Z (GMT). No. of bitstreams: 1 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) Made available in DSpace on 2013-09-30T19:22:36Z (GMT). No. of bitstreams: 2 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) WOS000275454100017.pdf.txt: 34647 bytes, checksum: b4efba760b21442eba43e7096f213b3e (MD5) Previous issue date: 2010-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:33:52Z No. of bitstreams: 2 WOS000275454100017.pdf: 273411 bytes, checksum: da2aeaea61ab57013d39ecf2456466e3 (MD5) WOS000275454100017.pdf.txt: 34647 bytes, ch…

ChemInform Abstract: Non-Conventional Methods and Media for the Activation and Manipulation of Carbon Nanoforms

2014

Very often, chemical transformations require tedious and long procedures, which, sometimes, can be avoided using alternative methods and media. New protocols, enabling us to save time and solvents, allow us also to explore new reaction profiles. This Tutorial Review focuses on the physical and chemical behavior of carbon nanoforms, CNFs (fullerenes, nanotubes, nanohorns, graphene, etc.) when non-conventional methods and techniques, such as microwave irradiation, mechano-chemistry or highly ionizing radiations are employed. In addition, the reactivity of CNFs in non-conventional media such as water, fluorinated solvents, supercritical fluids, or ionic liquids is also discussed.