Search

Using femtosecond laser irradiation and subsequent annealing, nanocomposite structures composed of spinel-type ferrimagnetic nanoparticles (NPs) and plasmonic metallic NPs have been formed space-selectively within glass doped with both α-Fe(2)O(3) and Al. The Faraday rotation spectra exhibit a distinct negative peak at around 400 nm, suggesting that the ferrimagnetic Faraday response is enhanced by the localized surface plasmon resonance (LSPR) due to metallic Al NPs. At the interfaces in the nanocomposites, the ferrimagnetism of magnetite NPs is directly coupled with the plasmon in the Al NPs. The control of the resonance wavelength of the magneto-optical peaks, namely, the size of plasmonic NPs has been demonstrated by changing the irradiation or annealing conditions.

The magneto‐optical properties of rare‐earth‐rich borate glasses prepared using a levitation technique were thoroughly investigated. Among the series of rare‐earth borate glasses, Tb2O3–B2O3 and Dy2O3–B2O3 glasses displayed remarkably large Faraday effects in the visible region. The Verdet constant of 58Tb2O3–42B2O3 reached −229 rad/T·m at 633 nm, surpassing the value of commercially available single‐crystalline Tb3Ga5O12. Compositions with a higher rare‐earth oxide content (60 mol%) than that of binary glasses facilitated the successful synthesis of Tb2O3–Dy2O3–B2O3 ternary glasses. The Verdet constant linearly increased with increasing Tb2O3 content for the glasses with 40 mol% B2O3. Results indicate that rare‐earth‐rich borate glasses are promising candidates for magneto‐optical applications in the visible region, and that the types and amounts of rare‐earth ion mainly affect these properties. [ABSTRACT FROM AUTHOR]

For the fiber‐based magneto‐optical (MO) devices, like Faraday optical isolator, the target MO glasses are supposed to strike a balance among the following properties: high Verdet constant, chemical and physical stabilities, compatibility with the fiber drawing process, and the connectivity to the silica glass fiber networks. In this work, we report on the MO application of Tb2O3‐Al2O3‐SiO2‐B2O3 (TASB) glasses as a derivative of the yttrium aluminum silicate (YAS) glass fiber systems which have been intensively studied for their huge potential in the context of all‐fiber lasers. We found that MO properties of the obtained TASB glasses vary systematically with the B2O3 contents. The effects of B2O3 on the local glass structures and the valence state of Tb ions were clarified via nuclear magnetic resonance, electron spin resonance, X‐ray photoemission spectroscopy, and Raman spectroscopy. B2O3 content in TASB glasses leads to a certain degree of depolymerization in glass network and most of Tb4+ ions from the raw material of Tb4O7 are reduced to Tb3+ ions even in air, resulting in an improved MO properties. Due to the relatively high Verdet constant (∼70 rad/T/m) and suitable rheology of the glass melt speculated from the thermal analysis, TASB glass system in this work is adaptable to stable fiber‐based Faraday effect devices. [ABSTRACT FROM AUTHOR]

Barium zinc phosphate glasses formulated in the xBaO–(60 − x)ZnO–40P2O5 composition line are investigated for their optical, thermal, and chemical characteristics. These as well as small stress‐induced birefringence were found to be governed by the BaO/ZnO substitution. In addition to the characterization of the properties, the phosphate network was qualitatively and quantitatively described in terms of Q2 and Q1 ratios by 1D 31P magic angle spinning nuclear magnetic resonance spectroscopy experiments that also showed the presence of Q0 sites. It turns out that the small perturbations of their photoelastic, magnetic, and chemical characteristics made these glasses very good candidates for use in polarization‐controlling optical devices. [ABSTRACT FROM AUTHOR]

Presents a study which examined the poling temperature variation of optical second-harmonic intensity induced by electrical poling in 30ZnO-70TeO[sub2], 5MgO-25ZnO-70TeO[sub2] and 10MgO-20ZnO-70TeO[sub2] glasses. Theoretical background; Computational approach; Results.

Abstract: Energy transfer process in soda-lime glasses co-doped with Gd3+ and Eu3+, where a ground state of Gd3+, 8S7/2, was selectively excited to a 6IJ state by a 275-nm pulsed laser irradiation, was studied based on a time-resolved luminescence spectroscopy. The luminescence decay rate at 313nm (Gd3+: 6P7/2 → 8S7/2) was observed to be (1.5±0.2)×102 s−1 (τ =6.6±0.6 ms) without Eu3+ and to increase monotonously with increasing co-doped Eu3+ concentration, giving an apparent quenching rate constant of (5.0± 0.5)×10−18 ion−1 cm3 s−1 (≈(1.9±0.2)×103 mol%−1 s−1) for a 6P7/2 state of Gd3+ ion with Eu3+. The relaxation rate of a 6IJ state to a luminescent state 6P7/2 in Gd3+ ion was estimated to be (1.8±0.2)×106 s−1 from the rise rate at 313-nm luminescence (τ rise ≈ 0.56μs), which was observed to be almost independent of the Eu3+ concentration. The luminescence intensity from Eu3+ at 591nm and 613nm monotonously increased with increasing Eu3+ concentration up to 0.33-mol% Eu3+, while it started decreasing at concentration of Eu3+ higher than 0.33-mol%, which was interpreted in terms of the resonant energy transfer to nearby Eu3+ resulting in the excitation to the Eu3+–O− charge transfer states. [Copyright &y& Elsevier]

Second-harmonic generation (SHG) has been observed in optically poled Y52 filter glass. Both encoded second-harmonic intensity and relaxation time for decay of second-harmonic intensity increase with an increase in poling time and power of laser at 532 nm used for optical poling. It is thought that the longer poling time and higher laser power for poling increase the number of positive holes and electrons, a periodic arrangement of which brings about automatically phase-matched SHG, leading to large second-harmonic intensity. The increase in relaxation time caused by optical poling for longer time and with higher laser power is presumably ascribed to thermal effect which can give rise to formation of positive holes and electrons at deeper energy levels. [Copyright &y& Elsevier]

The authors report on an intense blue emission centered at 420 nm under ultraviolet excitation from pentavalent tantalum ion-doped silicate glasses. The blue emission is distinctly different from emission due to defects in silica glass, which is also reflected in both absorption spectrum and remarkably enhanced emission. The authors suggest that localized Ta 5d0 energy level is responsible for the blue emission. [ABSTRACT FROM AUTHOR]

Studies the effect of poling on surface crystallization behavior of BaTiO[sub 3] in 15BaO-15TiO[sub 2]-70TeO[sub 2] glass and on second-harmonic generation of the resultant glass ceramics. Increase in the fraction of crystalline phases precipitated at the glass surface; Results of x-ray diffraction studies.

The variation of Ag2O solubility under air atmosphere with the chemical potential of Ag was measured for the MxO–B2O3–Al2O3 system by equilibrating with Ag–Au alloy of various Ag contents at 1273 and 1373 K. It was found that in this system the regular solution model is not valid for estimating the activity coefficient over a wide composition range. The activity coefficient of Ag2O in B2O3 at infinite dilution and first-order Gibbs energy interaction coefficients of Ag2O, Al2O3, and Na2O on Ag2O were determined from the Ag2O solubility data without assuming a regular solution. The increase of the Al2O3 solubility by addition of alkali oxide suggested that the glass melts were equilibrated with 2Al2O3·9B2O3 and not Al2O3 and the activity was considered to increase by the addition of alkali oxide. A good correlation was found between the activity coefficient of Ag2O and the optical basicity. [Copyright &y& Elsevier]