Search results for " effect"

Optical properties and photosensitivity of vacuum synthesized Ge-doped sol-gel amorphous SiO/sub 2/

2005

We report optical and electron paramagnetic resonance investigations of gamma ray irradiation effects in sol-gel Ge-doped amorphous SiO/sub 2/. The studied materials have Ge-doping levels up to 10/sup 4/ molar part per million and were densified by two routes differing for the atmosphere: O/sub 2/+N/sub 2/ or vacuum. The obtained results evidence that irradiation affects matrix sites inducing paramagnetic defects. Furthermore, the comparison between the two densification procedures shows that vacuum atmosphere induces higher radiation sensitivity.

Photoluminescence time decay of surface oxygen deficient centers in un‐doped and Ge‐doped silica

2005

We report a study of the emission decay from the singlet excited state of two fold coordinated Si and Ge centers stabilized on the surface of silica and Ge-doped silica. The PL lifetimes are of the order of nanoseconds and increase on decreasing the temperature. The results suggest that, for the surface centers, the phonon assisted intersystem-crossing process linking the excited states affects the decay rates, is effective down to low temperatures and is distributed because of the inhomogeneity of the defects. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Influence of specific codopants and post-treatments on Erbium Doped Fibers: Radiation behavior characteristics by CML

2010

Durcissement de matériaux pour l’optique et la photonique destinés à l’utilisation dans un environnement énergétique

2008

Influence du rayonnement X sur des fibres et préformes canoniques dopées au phosphore

2009

Near‐IR Radiation‐Induced Attenuation of Aluminosilicate Optical Fibers

2021

The X-ray radiation-induced attenuation (RIA) growth kinetics are studied online in different single-mode aluminosilicate optical fibers in the near-IR (NIR) domain to evaluate their potential in terms of dosimetry. The optical fibers differ by Al contents, core sizes, drawing parameters, and also by a preform deposition process. The data show no dependence of the RIA on all these parameters, a positive result for the design of point or distributed radiation detectors exploiting RIA to monitor the dose. The RIA growth rate is unchanged for dose rates changing from 0.073 to 6.25 Gy(SiO2) s−1, and the RIA linearly increases with the dose up to 2 kGy(SiO2). Small but noticeable RIA changes are…

Ge quantum well plasmon-enhanced quantum confined Stark effect modulator

2014

ABSTRACTWe theoretically and experimentally investigate a novel modulation concept on silicon (Si) based on the combination of quantum confinement and plasmon enhancement effects. We experimentally study the suitability of Ge/SiGe quantum wells (QWs) on Si as the active material for a plasmon-enhanced optical modulator. We demonstrate that in QW structures absorption and modulation of light with transverse magnetic (TM) polarization are greatly enhanced due to favorable selection rules. Later, we theoretically study the plasmon propagation at the metal-Ge/SiGe QW interface. We design a novel Ge/SiGe QW structure that allows maximized overlap between the plasmonic mode and the underlying Ge/…

Unravelling the Intertwined Atomic and Bulk Nature of Localised Excitons by Attosecond Spectroscopy

2021

The electro-optical properties of most semiconductors and insulators of technological interest are dominated by the presence of electron-hole quasi-particles, called excitons. The manipulation of excitons in dielectrics has recently received great attention, with possible applications in different fields including optoelectronics and photonics. Here, we apply attosecond transient reflection spectroscopy in a sequential two-foci geometry and observe sub-femtosecond dynamics of a core-level exciton in bulk MgF2 single crystals. Furthermore, we access absolute phase delays, which allow for an unambiguous comparison with theoretical calculations. Our results show that excitons surprisingly exhi…

Oral aphthous-like ulceration due to tiotropium bromide

2007

Unwanted side-effects of a drug therapy are well known to oral medicine specialists and other colleagues. Usually they manifest itself as dry mouth, taste disturbances, various allergic or toxic reactions on the lips and/or in the oral cavity. However, the list of the drugs which might induce unwanted reactions is everyday becoming longer as more and more drugs are introduced on the market. Certain problems when diagnosing and reporting unwanted side effects of the drugs exist as only accurate method of diagnosis is repeated drug use in controlled clinical setting where fatal consequences due to the anaphilactic shock could be avoided. We report a side effect reaction to tiotropium bromide …

Organic food consumption: The relevance of the health attribute

2020

During the last decades, organic food products have become the main sustainable alternative to conventional food consumption. Among the several organic food attributes that consumers recognize in organic food, healthiness has been reported as the primary motivation to buy products certified as organic. The objective of the current study is to assess the relative weight of the health attribute among other recognized organic food attributes. To achieve this aim, a multiple price list (MPL) methodology is adopted to elicit consumers&rsquo