Search results for "iTED"
showing 10 items of 2408 documents
Frequency dependence of the microwave surface resistance of MgB2 by coaxial cavity resonator
2014
Abstract We report on the microwave (mw) properties of a cylindrical MgB2 rod prepared by the reactive liquid Mg infiltration technology. The MgB2 rod, 94.3 mm long, is used as inner conductor of a coaxial cavity having a Cu tube as external conductor. By analyzing the resonance curves of the cavity in the different resonant modes and at different temperatures, we have determined the temperature dependence of the mw surface resistance, R s , of the MgB2 material, at fixed frequencies, and the frequency dependence of R s , at fixed temperatures. Our results show that the R s ( f ) curves follow a f n law, where n decreases on increasing the temperature, starting from n ≈ 2 , at T = 4.2 K , d…
Beta-delayed neutron spectroscopy by the TOF technique at IGISOL: 95Rb as a test case
2003
Nuclides with a large neutron excess have high Q β values, making it possible to extract the β-strength function (SF) over a large energy range using β-decay spectroscopy. However, because of the low neutron binding energies, neutron emission from excited states will occur and β-delayed neutron spectroscopy is required to determine the SF over the full Q β window.
Dispersion managed self-similar parabolic pulses
2008
International audience; We describe the propagation of a parabolic self-similar pulse in an anomalous dispersive nonlinear fibre. Given the capacity of a linearly chirped parabolic pulse to retain its typical shape over a short propagation distance, we introduce the concept of dispersion managed self-similar pulses and outline potential benefits in terms of spectral broadening enhancement.
Nanosecond thermo-optical dynamics of polymer loaded plasmonic waveguides
2013
The thermo-optical dynamics of polymer loaded surface plasmon waveguide (PLSPPW) based devices photo-thermally excited in the nanosecond regime is investigated. We demonstrate thermo-absorption of PLSPPW modes mediated by the temperature-dependent ohmic losses of the metal and the thermally controlled field distribution of the plasmon mode within the metal. For a PLSPPW excited by sub-nanosecond long pulses, we find that the thermo-absorption process leads to modulation depths up to 50% and features an activation time around 2ns whereas the relaxation time is around 800ns, four-fold smaller than the cooling time of the metal film itself. Next, we observe the photo-thermal activation of PLSP…
Luminescence of nano- and macrosized LaPO4:Ce,Tb excited by synchrotron radiation
2011
Abstract Comparing the luminescence properties of nanosized and macroscopic LaPO4:Ce,Tb powders are performed in wide spectral range using synchrotron radiation. In the present study, LaPO4:Ce,Tb nanopowder was produced by means of a microwave-induced synthesis in ionic liquids, whereas the bulk sample represents a commercial lamp phosphor. Emission and excitation of both, Ce3+ and Tb3+ luminescence, is observed to be different when comparing bulk and nanosized LaPO4:Ce,Tb. In particular, it was shown that the fine structure of the Ce3+ as well as the Tb3+ related emission is poorly resolved for the nanomaterial. It is suggested that the nanoparticles surface plays a key role regarding the …
Luminescence of rutile structured crystalline silicon dioxide (stishovite)
2014
Abstract Luminescence spectrum of synthetic mono-crystalline stishovite comprises a slow blue band at ~400 nm (~3.1 eV) and a fast UV band at ~260 nm (~4.7 eV), as well as some bands in near-infrared range of spectra. The NIR luminescence of stishovite crystal, excited with lasers 532 nm, 248 nm and 193 nm as well as x-ray, possesses several sharp lines. A zero phonon line is situated at 787 nm (1.57 eV) and grows with cooling. An anti-Stokes line is located at 771 nm (1.68 eV). This line disappears with cooling. In a powder sample of stishovite created by shock waves generated by the impact of a 50-m-diameter meteorite in Arizona 50,000 years ago, the PL broad blue band is situated at 425 …
Resonant Raman scattering of core-shell GaN/AlN nanowires.
2020
Abstract We have analyzed the electron–phonon coupling in GaN/AlN core–shell nanowires by means of Raman scattering excited at various wavelengths in the ultraviolet spectral range (335, 325 and 300 nm) and as a function of the AlN shell thickness. The detailed analysis of the multi-phonon spectra evidences important differences with excitation energy. Under 325 and 300 nm excitation the Raman process is mediated by the allowed A 1(LO) phonon mode, where the atoms vibrate along the NW axis. Considering its selection rules, this mode is easily accessible in backscattering along the wurtzite c axis. Interestingly, for 335 nm excitation the scattering process is instead mediated by the E 1(LO)…
Photoelectric response of localized states in silica glass
2019
This work was supported by the Latvian Science Council Grant No lzp-2018/1-0289.
Temperature dependent optical properties of stacked InGaAs/GaAs quantum rings
2008
4 páginas, 3 figuras, 2 tablas.-- MADICA 2006 Conference, Fifth Maghreb-Europe Meeting on Materials and their Applicatons for Devices and Physical, Chemical and Biological Sensors
Near infrared radio-luminescence of O2 loaded radiation hardened silica optical fibers: A candidate dosimeter for harsh environments
2014
We report on an experimental investigation of the infrared Radio-Luminescence (iRL) emission of interstitial O2 molecules loaded in radiation hardened pure-silica-core and fluorine-doped silica-based optical fibers (OFs). The O2 loading treatment successfully dissolved high concentrations of oxygen molecules into the silica matrix. A sharp luminescence at 1272 nm was detected when 2.5 cm of the treated OFs were irradiated with 10 keV X-rays. This emission originates from the radiative decay of the first excited singlet state of the embedded O2 molecules. The dose, dose-rate, and temperature dependencies of the infrared emission are studied through in situ optical measurements. The results s…