Influence of electron irradiation on optical properties of Bismuth doped silica fibers

Abstract

We report a study of the attenuation spectra transformations for a series of Bismuth (Bi) doped silica fibers with various contents of emission-active Bi centers, which arise as the result of irradiation by a beam of high-energy electrons. The experimental data reveal a substantial decrease of concentration of the Bi centers, associated with the presence of Germanium in silica glass, at increasing the irradiation dose (the resonant-absorption bleaching effect in germano-silicate fiber). In contrast, the spectral changes that appear in Bi doped alumino-silicate fiber have through irradiation a completely different character, viz., weak growth of the resonant-absorption peaks ascribed to the Bi centers, associated with the presence of Aluminum in silica glass. These results demonstrating high susceptibility of Bi centers to electron irradiation while opposite routes of the irradiation-induced spectral changes in Bi doped germanate and aluminate fibers seem to be of worth notice for understanding the nature of these centers.

Superbroad near-to-mid-infrared luminescence from Bi_5 ^3+ in Bi_5(AlCl_4)_3

“…The emission lifetime at room temperature typically ranges from hundreds of microseconds to several milliseconds. An additional absorption band at 1400 nm was observed by Dvoyrin et al and Bufetov et al in bismuth doped silica glass [1,[3][4][5]. In a non-oxide glass, Hughes et al reported absorption at ~1180nm, fluorescence lifetime of 175 µs at room temperature for an emission peak at ~1500nm [6].…”

“…The eutectic of (mol.%) 63 AlCl 3 -37 NaCl was selected as base composition, and the Al:Na ratio was kept constant throughout the study. Noteworthy, excess AlCl 3 facilitates formation of Lewis acidic tetrachloroaluminate AlCl 4 -units which further may stabilize the polycationic species. As raw materials, AlCl 3 (99.9%), NaCl (99.9%), BiCl 3 (99.9%) and Bi powder (99.99%) were employed.…”

“…In last decade, a new family of near infrared (NIR) emitting bismuth doped laser glasses has been discovered and soon become a subject of intensive study [1][2][3][4][5][6]. This has been primarily due to the material's intriguing spectral properties, especially superbroadband photoemission in the telecom spectral range, which currently cannot be obtained in traditional rare-earth based materials [1,[3][4][5]7,8].…”

“…This has been primarily due to the material's intriguing spectral properties, especially superbroadband photoemission in the telecom spectral range, which currently cannot be obtained in traditional rare-earth based materials [1,[3][4][5]7,8]. Reports on basic materials properties and corresponding optical devices have convincingly proven the potential for application in superbroad optical amplifiers for future telecommunication networks and laser sources [1][2][3][4][5][6][7][8][9][10][11][12][13][14] . For example, addition of specific amounts of reducing agents such as carbon powder or gaseous hydrogen to Bi-containing glass batches was observed to enhance NIR emission of the corresponding glasses [ 1 8].…”

“…When such NIR luminescent crystals are annealed in oxidizing atmosphere, the centers can be rendered inactive. As another example, exposure of Bi-doped glasses or crystals to femtosecond laser, γ-irradiation or electron beams can lead to the generation of NIR-active centers [4,9,[18][19][20]]. …”