Search results for "Dispersion"
showing 10 items of 1101 documents
Sensitivity optimization with cladding-etched long period fiber gratings at the dispersion turning point
2016
This work presents a refractive index sensor based on a long period fiber grating (LPFG) made in a reduced cladding fiber whose low order cladding modes have the turning point at large wavelengths. The combination of these parameters results in an improved sensitivity of 8734 nm/refractive index unit (RIU) for the LP0,3 mode in the 1400-1650 wavelength range. This value is similar to that obtained with thin-film coated LPFGs, which permits to avoid the coating deposition step. The numerical simulations are in agreement with the experimental results. This work was supported in part by the Spanish Ministry of Education and Science-FEDER TEC2013-43679-R. J.L. Cruz also acknowledges financial s…
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…
Multi-model ensemble simulations of olive pollen distribution in Europe in 2014: current status and outlook
2017
"Çalışmada 29 yazar bulunmaktadır. Bu yazarlardan sadece Bursa Uludağ Üniversitesi mensuplarının girişleri yapılmıştır” The paper presents the first modelling experiment of the European-scale olive pollen dispersion, analyses the quality of the predictions, and outlines the research needs. A 6-model strong ensemble of Copernicus Atmospheric Monitoring Service (CAMS) was run throughout the olive season of 2014, computing the olive pollen distribution. The simulations have been compared with observations in eight countries, which are members of the European Aeroallergen Network (EAN). Analysis was performed for individual models, the ensemble mean and median, and for a dynamically optimised c…
Nontemplate Synthesis of CH3NH3PbBr3 Perovskite Nanoparticles
2014
To date, there is no example in the literature of free, nanometer-sized, organolead halide CH3NH3PbBr3 perovskites. We report here the preparation of 6 nm-sized nanoparticles of this type by a simple and fast method based on the use of an ammonium bromide with a medium-sized chain that keeps the nanoparticles dispersed in a wide range of organic solvents. These nanoparticles can be maintained stable in the solid state as well as in concentrated solutions for more than three months, without requiring a mesoporous material. This makes it possible to prepare homogeneous thin films of these nanoparticles by spin-coating on a quartz substrate. Both the colloidal solution and the thin film emit l…
Understanding the role of Ti-rich domains in the stabilization of gold nanoparticles on mesoporous silica-based catalysts
2018
3 Tablae, 14 Figures.-- Supplementary material.-- © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Photon absorption by aqueous TiO2 dispersion contained in a stirred photoreactor
1991
We present a simple experimental method which allows the evaluation of the absorbed photon flow. The method is based on measurements of transmitted photon rates (by means of standard actinometer solutions) for different reactor thicknesses and/or catalyst concentrations. The method was applied to phenol degradation reaction carried out in a stirred batch phtotoreactor containing aqueous TiO 2 (anatase) dispersion, directly irradied by a 1,500 W Xe lamp
Hydrothermal synthesis of well-dispersed ultrafine N-doped TiO2 nanoparticles with enhanced photocatalytic activity under visible light
2010
Abstract Ultrafine nitrogen-doped TiO 2 nanoparticles with narrow particle size distribution, good dispersion, and high surface area were synthesized in the presence of urea and PEG-4000 via a hydrothermal procedure. TEM observation, N 2 adsorption, XRD, UV–vis spectroscopy, the Raman spectroscopy and XPS analysis were conducted to characterize the synthesized TiO 2 particles. The synthesized TiO 2 particles were a mixture of 49.5% anatase and 50.5% rutile with a size of around 5 nm. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive Brilliant Blue KN-R under both UV and visible light. The synthesized TiO 2 particles showed much higher photocat…