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The transformation behavior of free-volume defect in (80GeS 2 -20Ga 2 S 3 ) 100-x (CsI) x (x = 0, 5, 10, 15 mol%) chalcogenide glasses was studied by employing positron annihilation spectroscopic technique, which could reveal valuable information for in-depth understanding of nano-structural defects in glassy matrix. The results indicate that the structural changes caused by CsI additives can be adequately described by positron trapping modes determined with two-state model. The initial addition of CsI (x = 5 mol%) led to a void contraction, whereas, the void agglomeration occurred with the increase of CsI and the free-volume defects of the glasses were obviously reduced. The atomic density ρ is inversely proportional to the number of these defects. Meanwhile, the UV cut-off edge shifts toward short-wavelength with increasing of CsI. This study provides the valuable information of defects evolution in GeS 2 -Ga 2 S 3 -CsI glasses. [ABSTRACT FROM AUTHOR]

Glass-ceramics embedded Te and α-GeTe particles were fabricated from (GeTe 4 ) 85 (AgI) 15 chalcohalide glass using an appropriate heat-treatment at fairly low temperatures ranging from 160 to 190 °C for different times. The crystallization behavior and physical properties of the obtained samples were studied in detail. The glass transition temperature of crystallized samples increases with the elongation of crystallization times. And the results of mechanical properties show that, compared with the base glass, the crystallized samples present improved thermal shock resistance and fracture toughness, and meanwhile still remain its good IR transmittance. This study could provide an initial observation of crystallization in telluride glasses, and be of good guidance to fabricate novel telluride glass-ceramics that operating in far-IR spectral region ranging from 2.5 μm to 25 μm. [ABSTRACT FROM AUTHOR]

• Sn effect on glass-forming ability was studied. • Long-wavelength cut-off edge was extended. • Optical properties of Sn-modified ChGs were characterized. • Homogeneous ChG of Φ30 mm was prepared successfully. Chalcogenide glass is emerging as important IR materials for advanced athermal infrared (IR) optical systems because of its low thermal coefficient of refractive index. New chalcogenide glasses based on 75GeS 2 -15Ga 2 S 3 -10CsCl were developed through the substitution of GeS 2 by SnS 2. The introduction of heavier tin (Sn) results in the red shift of transmission window, both of visible and long-wavelength IR cut-off edges, the elevation of refractive index dispersion curves, and the decreasing of glass transition temperature. The formation of [SnS 4-x Cl x ] structural units, instead of [GeS 4-x Cl x ], should be responsible for the variation of these structural properties. In addition, homogeneous Sn modified GeS 2 -Ga 2 S 3 -CsCl chalcogenide glass of Φ30 mm was also prepared successfully, showing it of high potential for commercial applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Tm3+-doped chalcogenide glass exhibited a strong emission peak around 3.8μm. [•] An approximate model for the Tm3+-doped PCF amplifier was developed. [•] The amplifying characteristics of the designed PCF amplifier were worked out. [•] The designed PCF amplifier exhibits a large signal gain around 3.8μm. [ABSTRACT FROM AUTHOR]