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CO 2 molecule, one of the main molecules to create new life, should be probed accurately to detect the existence of life in exoplanets. The primary signature of CO 2 molecule is approximately 15 μm, and traditional S- and Se-based glass fibers are unsuitable. Thus, Te-based glass is the only ideal candidate glass for far-infrared detection. In this study, a new kind of Te-based chalcohalide glass system was discovered with relatively stable and large optical band gap. A traditional melt-quenching method was adopted to prepare a series of (Ge 15 Ga 10 Te 75 ) 100− x (CsBr) x chalcogenide glass samples. Experiment results indicate that the glass-forming ability and thermal properties of glass samples were improved when CsBr was added in the host of Ge–Ga–Te glass. Ge–Ga–Te glass could remarkably dissolve CsBr content as much as 85 at.%, which is the highest halide content in all reports for Te-based chalcohalide glasses. Moreover, Δ T values of these glass samples were all above 100 °C. The glass sample (Ge 15 Ga 10 Te 75 ) 65 (CsBr) 35 with Δ T of 119 °C was the largest, which was 7 °C larger than that of Ge 15 Ga 10 Te 75 host glass. The infrared transmission spectra of these glasses show that the far-infrared cut-off wavelengths of (Ge 15 Ga 10 Te 75 ) 100− x (CsBr) x chalcogenide glasses were all beyond 25 μm. In conclusion, (Ge 15 Ga 10 Te 75 ) 100− x (CsBr) x chalcogenide glasses are potential materials for far-infrared optical application. [ABSTRACT FROM AUTHOR]

Abstract: A serious of tellurium based chalcogenide glass were prepared and investigated. As it being transparent nearly up to 25μm and strong anti-hydrability, it becomes an optimized material for far-infrared application. Here, AgI was incorporated into the glasses acting as a glass modifier. With the help of AgI, a highest glass transition temperature, T g (151°C) can be obtained. Detailed physics and chemic properties of the glasses were analyzed with DTA and XRD. The infrared optical transmission spectra were studied with the help of FTIR and Raman test. A purifying process was adopted to eliminate the affections of impurities in the tellurium glass. These serious of glasses are all high transparent in the 8–20μm region, which fits for the applications of far-infrared optic imaging and sensing. [Copyright &y& Elsevier]

Abstract: A kind of novel fluorescence which possesses a potential application in wide-band optical amplifying is reported in this paper. With 975-nm LD laser pumping and Yb3+-assisted energy transferring, the fluorescence of Tm3+in the tellurite glass can be measured with emission spectra in 1.4- and 1.6- m bands, which would be continued to the 1.53 m of the Er3+. The full-width at half-maximum (FWHM) is 170nm( nm), and the lifetimes come up to 0.66 and 1.46ms. Then, an interpretation was given to the mechanism of IR fluorescence emission which is based on the energy transferring and up-conversion of Tm3+, Yb3+ and Er3+. [Copyright &y& Elsevier]

Abstract: Up-conversion luminescence characteristics under 975nm excitation have been investigated with Tb3+/Tm3+/Yb3+ triply doped tellurite glasses. Here, green (547nm: 5D4 → 7F4) and red (660nm: 5D4 → 7F2) up-conversion (UC) luminescence originating from Tb3+ is observed strongly, because of the quadratic dependences of emission intensities on the excitation power. Especially, the UC luminescence was intensified violently with the energy transfer from the Tm3+ ions involves in the Tb3+ excitation. To the Tb3+/Tm3+/Yb3+ triply doped glass system, a novel up-conversion mechanism is proposed as follows: the energy of 3G4 level (Tm3+) was transferred to 5D4 (Tb3+) and the 477-nm UC luminescence of Tm3+ was nearly quenched. [Copyright &y& Elsevier]

Abstract: A novel series of Ge–Te–BiI3 chalcogenide glasses were prepared by traditional melt-quenching method and the glass-forming region was determined. Properties measurements including density, Vis–NIR and infrared (IR) transmission spectra with FTIR, XRD, DSC were adopted to analyze the composition, structure and performance of the Ge–Te–BiI3 glass system. Based on the metallization criterion and band gap energy theory, the relationships between energy gap, metallization criterion and glass composition was investigated. The results show that with the addition of BiI3, the glasses-forming ability and thermal stability are improved. The values of energy band gap and metallization criterion are within the range of 0.627–0.343eV and 0.177–0.131, respectively. These series of glasses have wide optical transmission window from 2.2 to 25μm and can offer an alternative solution for far infrared transmitting applications. [Copyright &y& Elsevier]

Abstract: GeS2–In2S3–KI/AgI chalcohalide glasses were prepared by traditional melt-quenching method and the glass-forming region was determined. The dependence of glass properties on composition as formula of (100− x)(0.75GeS2–0.25In2S3)− x(In2S3–KI/AgI) was investigated. The allowed indirect transition of samples was calculated according to the classical Tauc equation. The results show that 50mol% AgI can be introduced in the glassy matrix while only 40mol% of KI can be incorporated in the GeS2–In2S3–KI glass system. GeS2–In2S3–AgI glass system has larger density, higher refractive index and better thermal stability, while GeS2–In2S3–KI glass system has shorter visible cut-off wavelength and higher optical band gap. [ABSTRACT FROM AUTHOR]

Abstract: The Ge–Ga–Se–S–CsCl glasses were prepared by the melting-quenching method. The absorption and transmission spectrum were measured under room temperature. It is found that these glasses have high broad spectral range of transparency from visible to far-infrared region (0.4–12μm). The relationship between the optical gap and chemical composition in terms of novel chalco-halide glasses is discussed based on the Pauling''s theory model, which is using the modified heats of atomization and the coordination number of the elements, to explain this phenomena for the first time. [Copyright &y& Elsevier]

Abstract: The glass-forming region of the GeSe2–In2Se3–KI system was reported firstly. The dependence of physical, thermal and optical properties on compositions as formula of (1− x)(0.8GeSe2–0.2In2Se3)–xKI (x =0, 0.1, 0.2, 0.3) chalcohalide glasses was investigated. The allowed direct transition and indirect transition, and Urbach energy of samples were calculated according to the classical Tauc equation. The results show that the glass system has good thermal stability and that there is an obvious blue-shift at the visible absorbing cutting-off edge. When the dissolved amount of KI increased from 0 to 30mol%, the direct optical band gap and the indirect optical band gap were in the range from 1.617 to 1.893eV and 1.573 to 1.857eV. With the decrease of the molar refraction the refractive index decreases, optical band gap and metallization criterion increase. The relationship between energy band gap and metallization criterion was analyzed and the optical properties of chalcohalide glasses were summarized. [Copyright &y& Elsevier]

Abstract: The absorption spectra and upconversion fluorescence spectra of Er3+/Yb3+-codoped natrium–gallium–germanium–bismuth glasses are measured and investigated. The intense green (533 and 549nm) and red (672nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga2C3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga2O3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740cm−1. The studies indicate that Bi2O3–GeO2–Ga2O3–Na2O glasses may be potential materials for developing upconversion optical devices [Copyright &y& Elsevier]

Abstract: Dy3+ doped 40GeSe2–25Ga2Se3–35CsI (GGC) glass was synthesized, and optical spectrum, such as infrared transmission and Vis-Nir absorption was measured. Base on the Judd–Ofelt theory, the three Judd–Ofelt parameters Ω t (t =2, 4, 6) were calculated and the results were compared with other chalcogenide glasses. The small Ω 2 in GGC glass is ascribed to the weak covalency of Se–Dy bond. The theory of crystallization kinetics under non-isothermal condition was developed, and was applied to analyze this Dy3+ doped GGC glass. From the heating-rate dependence of crystallization temperature, the activation energy for crystallization E =148kJ/mol is obtained, and this value is much smaller than that of the undoped glass host, indicating the introduction of Dy3+ ions into the GGC glass will get the host crystallized easily. [Copyright &y& Elsevier]

Abstract: The B2O3 was introduced into the Er3+ doped TeO2–ZnO–Na2O glass to increase the phonon energy of the host. The effect of B2O3 on the non-radiative rate of the 4I11/2 → 4I13/2 transition of Er3+, the lifetime of the 4I11/2 and 4I13/2 levels, the green and red upconversion emissions intensity, and the 4I13/2 → 4I15/2 emission intensity was discussed. The results show that the phonon energy of boro-tellurite glass is close to that of germanate glass and is quite smaller than that of borate glass. The lifetime of 4I11/2 level and the upconversion emissions decrease with increasing B2O3 concentration. The higher OH group concentration presented in the boro-tellurite glass may shorten the lifetime of 4I13/2 level and also reduce the quantum efficiency of 4I13/2 → 4I15/2 emission. The future dehydrating procedures are suggested to enhance the efficiency of amplification at 1.5μm band. [Copyright &y& Elsevier]

It is well known that, the incorporation of halide will improve the optical properties of chalcogenide glasses with a broad transparent range. Here, we investigated the optical properties and structure of Ge-As-Se-I glasses in order to disclose the role of halogen iodine in the formation of chalcogenide glassy network. It was found that, refractive index, zero dispersion wavelength and glass transition temperature Tg decrease with increasing iodine contents, while the cut-off edge (λ vis) in the shorter wavelength blue-shifts apparently, and the whole transmission range is expanded widely. The glasses show good chemical stability against moisture. The zero dispersion wavelength of the glasses can be decreased to 4.32 μm by iodine-doping. The evolution of Raman spectra of the glasses indicates that, there is no obvious peak of iodine in Ge-As-Se-I glasses and the dominated glassy network are still the (Ge Se) heteropolar bonds. Unlabelled Image • These novel glass samples possess wide IR transparent window of 0.75-18 μm. • The ZWD of the glass can be decreased to 4.32μm while the refractive index is as low as 2.162 @1.7μm. • The strong absorption peaks of Ge O bond(12.5μm) and H 2 O(6.31μm) are all eliminated after effective purification. [ABSTRACT FROM AUTHOR]