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Chlorine or chlorides are usually used as a dehydrating agent for removing the O‐H or S(Se)‐H in the preparation of high‐purity chalcogenide glasses. However, the residual chlorine in some rare‐earth ions doped chalcogenide glasses was found to have a great negative impact on fluorescence emission. In this work, the effect of residual chlorine on the fluorescence emission of Dy3+ ions in serial (Ge)GaAsSbS glasses was studied quantitatively, and the reasons were discussed. Cl2 gas and SbCl3 were used as the source of chlorine and their residual contents were controlled by the post‐distillation process and added content, respectively. The results can give some suggestions for how to eliminate the negative effects of chlorine and improve the glass' optical gain properties. [ABSTRACT FROM AUTHOR]

By conventional melt‐quenching techniques, a series of Dy3+‐doped (0.1 to 1.0 wt%) Ga5Ge20Sb15S60 bulk glasses were fabricated and their potential for developing mid‐infrared fiber laser beyond 4 μm were evaluated, in which the optimal Dy3+ doping concentration was found to be 0.3 wt% and the largest laser quality factor value (σe × τmea = 2.62 × 10−23 cm2 s) among all of the Dy3+‐doped chalcogenide glass was obtained. On this basis, through using the chemical purification methods with chlorine gas combined with the dynamic distillation process, the high‐purity GGSS glasses with low O–H and S–H absorptions were successfully fabricated, which was confirmed by the optimized mid‐infrared linear transmittance and improved fluorescent lifetimes of Dy3+: 6H13/2, 6H11/2 levels. Furthermore, for the first time to the best of our knowledge, the Dy3+‐doped, single‐mode, and double‐cladding chalcogenide fibers with the core/cladding ratios of 125:60:11 and 125:66:11.5 were achieved by a multistage rod‐in‐tube fiber drawing process and extrusion methods, respectively. The GeS2‐based fiber exhibits excellent transmission performance at 1.0‐5.0 μm: 3.0 dB/m at 2.9 μm (O–H), 2.4 dB/m at 4.1 μm (S–H). Combining the advantages of high‐purity, high doping concentration and single‐mode double‐cladding structure, the optimized active fiber should be an ideal efficient and low‐threshold medium toward mid‐infrared fiber laser beyond 4 μm. [ABSTRACT FROM AUTHOR]

To develop high‐performance magneto‐optical chalcogenide glasses and clarify the mechanisms of the Verdet constant, a series of GeS2–Sb2S3–PbI2 chalcogenide glasses were designed and fabricated, and their Faraday effects were investigated at a wavelength of 980 nm. A new parameter, that is, average polarizability, was proposed, and the results show that the Verdet constant has a good linear relationship with average polarizability, meaning that the Verdet constant of a chalcogenide glass can be directly estimated by its chemical constituents. The Verdet constant is as large as 0.200 min G−1 cm−1 at 980 nm for 22.5GeS2–67.5Sb2S3–10PbI2 composition glass, which is the largest value reported thus far for sulfide glasses; this glass also possesses good thermal and optical properties and therefore might be an attractive candidate for mid‐infrared magneto‐optical device applications. [ABSTRACT FROM AUTHOR]

The multi‐component glass fibers have demonstrated their unique advantages in the application of single‐frequency lasers due to their higher solubility of rare‐earth ions and thus a higher gain per unit length in a compact fiber laser cavity. In this study, multi‐component yttrium aluminosilicate (YAS) fiber with high doping concentration of Yb3+ was prepared by the "melt‐in‐tube" (MIT) method. A unit‐length gain of 3 dB/cm was obtained in a 4.4 cm‐long YAS fiber, the laser output slope efficiency reached 23.8% in a 10 cm‐long Yb:YAS fiber. Single‐frequency laser operation was achieved in a 1.7‐cm‐long Yb:YAS active fiber. To the best of our knowledge, this is the first demonstration of single‐frequency laser with this YAS glass fiber as gain medium. The novel multi‐component YAS fiber can be applied as a new gain material to realize single‐frequency fiber laser. [ABSTRACT FROM AUTHOR]

Abstract: Yttrium aluminosilicate (YAS) glass core fibers with different doping concentration of Tm3+ were fabricated by a “Melt‐in‐Tube” method from YAG polycrystalline ceramics. The effect of Tm3+ concentration on the spectroscopy of YAG ceramics and laser performance of YAS fibers were discussed. A homemade linear all‐fiber laser based on the obtained 15% Tm3+‐doped YAS fiber shows an optimized slope efficiency of 12.8%. The YAS fibers have been proven to be practical to achieve extremely high Tm3+ doping concentration and are a promising option for the 2.0 μm laser. [ABSTRACT FROM AUTHOR]

Abstract: A graded‐index fiber with yttrium aluminosilicate (YAS) glass core was fabricated by a “Melt‐in‐Tube” method. The refractive index and stress profiles of the fibers exhibit a highly symmetrical gradient tendency along the radial axis which is in accordance with the results of element migration. Based on the formation mechanism of YAS glass core, the relationships between the refractive index/stress profile and the spontaneous migration are discussed. A linear all‐fiber laser based on the obtained fiber shows a laser output threshold of 11.48 mW and slope efficiency of 8.3%. The near‐field beam intensity distribution of fiber laser with spectrum FWHM of 0.24 nm indicates the good laser beam quality. The facile “Melt‐in‐tube” method was proved to be reliable in designing graded‐index fiber through the dissolution and diffusion process, which is more advanced than commonly used “Rod‐in‐tube” method. [ABSTRACT FROM AUTHOR]

The Faraday effects of Ge-Ga-Sb(In)-S serial chalcogenide glasses were investigated at the wavelengths of 635, 808, 980, and 1319 nm, respectively. The compositional dependences were analyzed and associated influencing factors including the absorption edge, the concentration of Sb3+/In3+ ions, and the wavelength dispersion of refraction index were discussed. 80GeS2·20Sb2S3 composition glass was found to have the largest Verdet constant ( V=0.253, 0.219, 0.149, and 0.065 min·G−1·cm−1 for wavelengths 635, 808, 980, and 1319 nm, respectively) in these glasses, which is larger than that of commercial diamagnetic glasses (Schott, SF 6, V=0.069 min·G−1·cm−1@633 nm, for example). Sb3+ ions with high polarizability possessing s 2 -sp electron jumps involving 1 S 0→ 1 P 1, 3 P 0,1,2 transitions are responsible for large Verdet constant, and Becquerel rule is proved to be an effective guidance for estimating the Verdet constant and further optimizing the compositions in chalcogenide glasses. [ABSTRACT FROM AUTHOR]

New 39Ar−40Ar radiometric data are presented. They concern the metasedimentary series and the orthogneiss pluton of Kangmar. Ages as young as 13 Ma are found which may be related either to the metamorphism or to the resetting of the minerals during the emplacement of the numerous intrusive bodies into the North Himalaya Belt. Inherited excess argon is found in micas from the orthogneiss previously dated at 562 Ma. These bodies are constituted by leucogranitic magmas, the biotites and the muscovites of which the granites intrude (Lhagoi Kangri Massif). Same range of ages is found in the High Himalaya Belt for micas from leucogranites. Ages as young as 4 Ma are found on micas from the southern part of the cross section between Nyalam and Zham. The recent uplifts and/or the movement of recent normal faults may be related to these young ages. [ABSTRACT FROM AUTHOR]