Search results for "Silica glass"

Luminescence of localized states in oxidized and fluorinated silica glass

2019

This work was supported by the Latvian Science Council Grant No lzp-2018/1-0289.

Third-harmonic generation in optical microfibers: From silica experiments to highly nonlinear glass prospects

2012

International audience; Using optical microfibers, phase matching between different propagation modes allows for third-harmonic generation (THG). After detailing the relevant phase matching conditions and overlap integrals, we provide a comparison between THG effective efficiencies in silica and tellurite glasses. We also explain the relatively easy, wideband, conversion that we observe experimentally in silica glass microfibers, from 155 mu m to the green, by the geometry of the tapering region.

Laser wavelength effects on the refractive index change of waveguides written by femtosecond pulses in silica glasses

2018

We investigate the influence of two fs-laser wavelengths (343 and 800 nm) on the induced refractive index change (Δn) of waveguides written in silica materials. Results show that Δn is higher for waveguides photo-inscribed with UV photons.

Absorption edge in silica glass

2005

Measurements of optical absorption in the v-UV range in a variety of silica glass are used to determine the width of the absorption edge (Urbach energy). Measured values range from 60 meV up to 180 meV. So high a variability over silica types is tentatively ascribed to the different disorder degree, which characterizes different materials.

Luminescence of non-bridging oxygen hole centers as a marker of particle irradiation of {\alpha}-quartz

2021

The origin of the "red" emission bands in the 600 nm-700 nm region, observed in quartz crystals used for luminescence dating and environmental dosimetry, is still controversial. Their reported spectral and lifetime characteristics are often similar to those of oxygen dangling bonds ("non-bridging oxygen hole centers, NBOHCs") in glassy silicon dioxide. The presence of these "surface radical type" centers in quartz crystal requires sites with highly disordered local structure forming nano-voids characteristic to the structure of glassy SiO2. Such sites are introduced in the tracks of nuclear particles ({\alpha}-irradiation, neutrons, ions). In case of electrons they are created only at large…

Structural organization of silanol and silicon hydride groups in the amorphous silicon dioxide network

2011

We present a study on the effects of an isothermal annealing treatment on a-SiO 2 having a significant content of silanol hydride groups (Si-H). We examined the properties of the IR absorption bands of silanol (Si-OH) and silicon hydride groups as a function of the duration of the thermal treatment. We showed that the Si-OH and Si-H groups contents decrease in a linearly correlated way. The annealing dynamics suggest that the two species are close to each other in the amorphous network. We showed that the profile of the silanol groups absorption band is the same as that observed in other commercial a-SiO 2 materials, irrespectively of the concomitant presence of nearby Si-H groups, and, mor…

Erratum to ‘Raman spectroscopy of β-irradiated silica glass’ by B. Boizot, S. Agnello, B. Reynard, R. Boscaino and G. Petite [J. Non-Cryst. Solids 32…

2004

Optical Absorption of Excimer Laser‐Induced Dichlorine Monoxide in Silica Glass and Excitation of Singlet Oxygen Luminescence by Energy Transfer from…

2021

An optical absorption (OA) band of interstitial dichlorine monoxide molecules with peak at 4.7 eV and halfwidth 0.94 eV is identified in F2 laser - irradiated (photon energy=7.9 eV) synthetic silica glass bearing both interstitial O2 and Cl2 molecules. Alongside with intrinsic defects, this OA band can contribute to solarization of silica glasses produced from SiCl4. While the formation of ClClO is confirmed by its Raman signature, its structural isomer ClOCl may also contribute to this induced OA band. Thermal destruction of this band between 300C and 400C almost completely restores the pre-irradiation concentration of interstitial Cl2. An additional weak OA band at 3.5 eV is tentatively a…

Gd 3+ -doped sol-gel silica glass for remote ionizing radiation dosimetry

2019

Gadolinium-doped silica glass was prepared, using the sol-gel route, for ionizing radiation dosimetry applications. Such a glassy rod was drawn to a cane at a temperature of 2000 °C. The structural and optical properties of the obtained material were studied using Raman, optical absorption, and photoluminescence spectroscopies. Thereafter, a small piece of this Gd-doped scintillating cane was spliced to a transport passive optical fiber, allowing the remote monitoring of the X-ray dose rate through a radioluminescence (RL) signal. The sample exhibited a linear RL intensity response versus the dose rate from 125 µGy(SiO2)/s up to 12.25 Gy/s. These results confirm the potentialities of this m…

Raman spectroscopy study of β-irradiated silica glass

2003

International audience; Natural and synthetic silica glass samples with different OH content have been submitted to β-irradiation at different doses from 106 to 5 × 109 Gy in a Van de Graaff accelerator. Structural changes under irradiation have been analyzed by Raman spectroscopy. The main findings are: (i) a decrease of the Si–O–Si angular dispersion and the average Si–O–Si angle as a function of dose and (ii) an increase of number of three-membered SiO4 ring concentration during irradiation. These results show therefore that purely electronic excitation from β-irradiation induces in a-SiO2 small but significant structural changes of the SiO4 membered ring statistics (size and dispersion)…