Effect of electron irradiation on the optical properties of bismuth doped hafnia-yttria-alumina-silicate fiber

We report a study on transformations in absorption and emission spectra of novel bismuth (Bi) doped hafnia-yttria-alumina-silicate fiber, which arise as the result of bombardment by high-energy (beta) electrons. Among the featuring data obtained, we reveal substantial growth of `active' Bi center content in the fiber core-glass with increasing beta-irradiation dosage, resulting in dose-dependent intensification of the resonant-absorption bands and enhancement of the emissive potential of the fiber in near-IR, inherent to these centers. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Effects of electron-irradiation darkening and its posterior bleaching by light in novel Cr-Mg-YAS fiber

Two remarkable effects for the recently invented chromium-magnesium (Cr-Mg) co-doped yttria-alumino-silicate fiber are reported: (i) strong and spectrally peculiar darkening under the action of energetic (6 MeV) beta-electrons with dosage up to 1.0 x 10(15) cm(-2) and (ii) posterior optical bleaching of the darkening loss at exposure to low-power (of a mW-range) 633 nm light. Both phenomena are revealed to be conspecific to co-doping the fiber with Mg and to the presence of versatile valence forms of Cr ions. The reported results seem to be impactful for exploiting fiber of such type for dosimetry and in space technology

Effects of elevating temperature and high-temperature annealing upon state-of-the-art of yttia-alumino-silicate fibers doped with Bismuth

We report an experimental analysis of attenuation and fluorescence (at low-power 750-nm excitation) spectra' transformations in yttria-alumino-silicate fiber doped with Bismuth (Bi), which occur at higher than room, but not exceeding 700 degrees C, temperatures. As well, we address impact of elevating temperature upon the fiber's basic characteristics, such as fluorescence/resonant-absorption saturation, fluorescence lifetime, and pump-light backscattering, given by the presence of Bi-Al related active centers (BACs). The experimental data reveals dramatic impact of heating and high-temperature annealing in excess of 500...550 degrees C on the fiber's state-of-the-art, expressed as significant rise of resonant absorption, enhancement of BACs NIR fluorescence, and reduction of scattering loss. In the meantime, such microscopic parameters of the fiber as BACs fluorescence lifetime and saturation power are found to be kept almost unchanged in its post-annealed state as compared to the pristine one. Possible mechanisms responsible for the phenomena and advantages of utilizing temperature-treated fiber of such type for lasing/amplifying purposes are discussed. (C) 2016 Optical Society of Americ

Hafnia-yttria-alumina-silica based optical fibers with diminished mid-IR (> 2 mu m) loss

Fabrication details and basic characteristics of a set of novel multimode hafniayttria- alumina-silicate (HYAS) core-glass based fibers, one of which is co-doped with bismuth (Bi), for the mid-IR (> 2 mu m) spectral range are reported. It is demonstrated that fibers of this type possess low fundamental loss in the spectral range beyond 2 mu m, lowered by fewer times as compared to conventional silica-based ones, even at moderate (units of mol.%) co-doping with hafnium. This makes them attractive for versatile mid-IR applications. Furthermore, HYAS core-glass fiber co-doped with Bi is revealed to have all the signs of `active' (fluorescing) Bi-related centers, thus being suitable for lasing/amplifying in the nearIR spectral range. (C) 2017 Optical Society of Americ