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Abstract: 0.2wt.% Dy3+-doped and 0.2wt.% Dy3+, 0.5wt.% Tm3+-codoped (100-x)GeS2 ·xIn2S3 (x=5,10,15,20,25) chalcogenide glasses were prepared. Their spectroscopic properties were analyzed based on absorption (ranges from 500 to 3000nm) and emission (ranges from 1000 to 4700nm) measurements. The Judd–Ofelt strength parameters Ωt (t =2, 4, 6) and the spectroscopy parameters Arad , β and τrad were calculated, and the σemi of the 1330, 2930 and 4320nm fluorescences were estimated. These Dy3+-doped and Dy3+, Tm3+-codoped Ge–In–S chalcogenide glasses are valuable materials for using in 1.3μm fiber-amplifiers and 2–5μm mid-infrared laser devices. [Copyright &y& Elsevier]

In this work, the population bottleneck of Er3+: 4I 11/2 → 4I 13/2 was overcome for the first time in heavy Er3+/Pr3+ co-doped TeO 2 –BaF 2 –La 2 O 3 –LaF 3 (TBLL) low hydroxyl fluorotellurite glasses. Infrared emission spectra and fluorescence lifetime decay curves reveal that Pr3+ ions could deplete the electrons from the Er3+: 4I 13/2 level faster than those from the Er3+: 4I 11/2 under 980 nm excitation. Specifically, the energy transfer (ET) efficiency of the Er3+: 4I 13/2 → Pr3+: 3F 3,4 process (ET1) reached 96.27%, while that of the Er3+: 4I 11/2 → Pr3+: 1G 4 process (ET2) is only 2.17% in the Er3+/Pr3+ co-doped glass. Additionally, the energy transfer mechanism of Er3+ and Pr3+ ions was investigated using the Dexter theory, where the energy transfer microscopic parameters C D-A are 13.21 × 10−40 cm6/s and 0.89 × 10−40 cm6/s for the ET1 and ET2 processes, respectively. Finally, a numerical simulations laser model was developed to discuss the laser properties of the Er3+/Pr3+ co-doped TBLL fibers. The simulation results indicate that a 2.7 μm laser with a maximum output power of 2.26 W and slope efficiency of 13.89% could be achieved when the fiber background loss is reduced to 0.5 dB/m. The above results suggest that the Er3+/Pr3+ co-doped TBLL glass has great potential applications in mid-infrared fiber lasers. [ABSTRACT FROM AUTHOR]

A type of Tm-doped silica fiber laser with narrow-linewidth and output wavelength near 1750 nm was firstly presented, by using a 1550 nm Er-doped fiber laser pump source and a volume Bragg grating (VBG). By means of a 15 cm Tm-doped fiber, a 400 mW continuous wave (cw) at ~1750 nm with FWHW of ~54 pm was generated, corresponding to an average slope efficiency up to 23.5% with respect to absorbed pump power. The influence of gain fiber length on the spectrum wavelength has been investigated in detail. All experimental results demonstrate that this fiber laser will be an effective and promising pump source for mid-IR laser output. [ABSTRACT FROM AUTHOR]

The 2.85 μm band has garnered significant attention for its wide range of applications in the mid-infrared region, and Ho3+ doped fluorotellurite fiber shows great promise as a gain medium for the 2.85 μm fiber laser. To achieve efficient population inversion for Ho3+ ions at 2.85 μm, Ho3+/Nd3+ co-doped fluorotellurite glasses with low hydroxyl were synthesized. The deactivation effect of Nd3+ ions to Ho3+: 5I 7 levels was investigated through emission spectra and lifetime decay curves under 890 nm excitation. The results show that Nd3+ ions can effectively quench the Ho3+: 2.05 μm emission and help the Ho3+: 5I 6 → 5I 7 transition to overcome the bottleneck of particle population inversion. Ultimately, the particle population inversion corresponding to 2.85 μm luminescence was realized in the Ho3+/Nd3+ co-doped fluorotellurite glass, and indicates that a maximum of 1.64 W laser at 2.85 μm with a slope efficiency of 8.72 % can be realized under 890 nm pump by numerical simulations. • Achieved low hydroxyl absorption in fluorotellurite glass. • Overcoming the population inversion bottleneck of the Ho3+: 5I 6.→ 5I 7 transition • Energy transfer mechanisms between Ho3+ and Nd3+ ions are discussed. • One-watt mid-infrared laser achieved theoretically in Ho3+/Nd3+ co-doped glass. [ABSTRACT FROM AUTHOR]

0.2%–3% weight of Dy 3+ ions doped 64GeS 2 ·16Ga 2 S 3 ·20CdI 2 glasses were synthesized, and their spectroscopic properties were investigated. It was shown that the host glass could dissolve as much as 3% Dy 3+ ions without deteriorating the glass transparency. The mid-infrared (MIR) emissions of the glasses did not present remarkable concentration quenching when the Dy 3+ ions concentration was less than 0.6%. It was also shown that the MIR emission properties could be significantly improved by reducing S H/O H impurities in the glasses. The spectral analyses indicated that the 2.9 and 4.3 μm emissions of Dy 3+ ions in the glass showed relatively large stimulated emission cross sections. The glass doped with as high as 0.4% Dy 3+ ions was successfully drawn into fibers, indicating good potential of the doped glass for MIR lasers. [ABSTRACT FROM AUTHOR]