International audienceIn this paper, we report a novel phenomenon in GeS2−In2S3−CsI chalcohalide glasses doped with Tm3+ ions. Under irradiation with an 808 nm laser diode, a bright red emission centered at 700 nm is observed for the first time. By codoping with different concentration of Er3+ ions, emission can be tuned from monochromatic red to green. The Er3+ ions codopant and higher concentration of Tm3+ ions are favoring the 700 nm red emission. Meanwhile, the indium (In) contents plays a significant role on the enhanced upconversion and near-IR emissions. These observations are interesting and may enable the device based on the chalcohalide glass to meet the specific color demands, which have potential applications in the fields of optical and solid state lasers

The near-IR emission spectra of Er 3+ -Tm 3+ codoped 70GeS 2 -20In 2 S 3 -10CsI chalcohalide glasses were studied with an 808 nm laser as an excitation source. A broad emission extending from 1.35 to 1.7 m with a FWHM of ϳ160 nm was recorded in a 0.1 mol.% Er 2 S 3 , 0.5 mol.% Tm 2 S 3 codoped chalcohalide glass. The fluorescence decay curves of glasses were measured by monitoring the emissions of Tm 3+ at 1460 nm and Er 3+ at 1540 nm, and the lifetimes were obtained from the first-order exponential fit. The luminescence mechanism and the possible energy-transfer processes are discussed with respect to the energy-level dia The rapid development of the telecommunications industry and the demand for having additional amounts of information transmitted over the current existing fiber-optic networks have stimulated the need for wider band transmission. In particular, the application of dense wavelength-division multiplexing (WDM) is growing in popular use. In common applications of erbium-doped silica-based amplifiers today, the characteristics of the erbium spectra have constrained the bandwidth of the spectra of the amplifiers. To improve this constraint, researchers look to multiple rare-earth (RE) ions codoping [1,2]. The Tm 3+ emission ( 3 H 4 → 3 F 4 transition) around 1470 nm allows a band extension in the spectral range corresponding to the S-band amplifier region, on the short wavelength side of the conventional Erdoped fiber amplifier C ϩ L bands at 1530-1570 nm [2]. However, silica and most silica-based glasses are not as suitable for Tm-gain devices as they are for Er ones. This is due to the fact that the transition Tm 3+ : 3 H 4 → 3 F 4 suffers appreciable multiphonon deexcitation because of the relatively high maximum phonon energy ͑1100 cm −1 ͒ of these glasses [1,3]. Therefore, the host matrix having low phonon energy to minimize multiphonon relaxation becomes essential. Chalcogenide glass is one of the most promising candidates because of its low phonon energy. Moreover, the addition of halides into sulfide glass dramatically improves the radiative properties of RE ions [4,5].For this Letter, Er 3+ -Tm 3+ codoped chalcohalide glasses were prepared, and their broad emissions in the near-IR region were investigated using the pump excitation at 808 nm. The possible energy transfer processes between Er 3+ and Tm 3+ ions are also discussed.Glasses were prepared in 6 g batches from highpurity elements (Ge, In, and S, 5N) and compounds (CsI, Tm 2 S 3 , and Er 2 S 3 , 3N). The host glass was 70GeS 2 -20In 2 S 3 -10CsI (mol.%), which was chosen from [6]. Tm and Er of different contents were codoped as (mol.%): 0.25Tm 2 S 3 -0.05Er 2 S 3 (G1), and xTm 2 S 3 -0.1Er 2 S 3 [x = 0.25 (G2), 0.5 (G3), and 1.0 (G4)] The batches were melted at 950°C in evacuated ͑10−5 Pa͒ fused-silica ampules for 12 h and then quenched in water. The obtained glass samples were annealed at 300°C for 2 h. Samples with size of 10 ϫ 10ϫ 2 mm 3 were well polished to good optical quality. The absorption spectrum of the sample was performe...

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