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Infrared graded‐index (GRIN) lenses are desirable for realizing miniaturization and lightweight of infrared imaging systems. Chalcogenide glasses have excellent infrared transparency, good rheological property, and large refractive index range, making them preferred materials for infrared GRIN lenses. In this work, aiming to find thermally matched chalcogenide compositions with high refractive index contrast for preparing GRIN glasses by the stacking diffusion approach, we investigated characteristic temperature, thermal expansion coefficient and refractive index of Ge‐As‐Se and Ge‐As‐Se‐Te glasses, optimized the glass compositions, and evaluated the feasibility of preparing GRIN glass using the optimized chalcogenide glass powders. It is found that Ge20As20Se20Te40 and Ge12As22Se66 glasses have similar softening temperature (247°C vs. 249°C), reasonably difference of thermal expansion coefficient (3.8 ppm/K), and large refractive index contrast (∼.48). The glass powders with composition xGe20As20Se20Te40‐(1‐x) Ge12As22Se66 can be hot‐pressed into glass disks with good transmittance at the same temperature and pressure. Graded refractive index profile is formed near the interface between the layers after the co‐pressed glass is thermally treated. These results demonstrate the prospect of the compositions for preparing infrared GRIN glasses. [ABSTRACT FROM AUTHOR]

An environment friendly nonlinear chalcogenide glass fiber with a Ge-Sb-Se core and a Ge-Se cladding is fabricated for bright broadband mid-infrared ( MIR) supercontinuum ( SC) generation. The fabricated Ge-Sb-Se/Ge-Se fiber with a core diameter of 6 μm shows zero group velocity dispersion at ~4.2 μm and ~7.3 μm. By pumping the fiber with a length of 11 cm at 4.485 μm with 330 fs pulses, we achieve a SC covering the 2.2-12 μm spectral range and with an output average power of ~17 mW. This bright broadband SC source is promising for high-resolution MIR spectroscopy. [ABSTRACT FROM AUTHOR]

High-purity Ge-As-Se and Ge-As-S chalcogenide glasses were prepared by modified physical and chemical purification techniques. Using the purified glasses, step-index fibers with a small core (~5.5 μm) and large numerical aperture (~1.3) were fabricated. When a 13.5-cm-long fiber was pumped with 320 fs pulses at a repetition rate of 10.5 MHz at 4.1 μm, supercontinuum spanning from ~1.8 to ~9.8 μm with a dynamic range of ±10 dB and an average power of ~3 mW was generated. [ABSTRACT FROM AUTHOR]

The production of a broadband supercontinuum spanning from 1.8 μm to >7.5 μm is reported which was created by pumping a chalcogenide glass waveguide with ≈320 fs pulses at 4 μm. The total power was ≈20 mW and the source brightness was [ABSTRACT FROM AUTHOR]

A Co2+:ZnS-doped chalcogenide glass with broadband mid-infrared emission was prepared by using a hot uniaxial pressing process. The refractive index difference (Δn) between matrix glass (As 2 S 5) and crystal (Co2+:ZnS) was controlled to be 0.0042 in the emission spectral range of Co2+ to minimize the scattering effect. An ultrabroadband mid-infrared emission of 2–4 μm was observed at room temperature in the samples after excitation by using a commercially available laser diode of 1550 nm. The significant changes in the lifetime and fluorescence intensity of Co2+:ZnS-doped chalcogenide glass were measured in the temperature range of 90–290 K. A resolution of approximately 0.18 K was observed when used as a temperature detector. Furthermore, a gas-sensing device was built by using the strong and broad emissions of the sample, and the detection sensitivity of butane reached 56 ppm. These results show that this glass-ceramics can be used as optical sensing of gas and temperature. [ABSTRACT FROM AUTHOR]

A step-index chalcogenide fiber with a rectangular core and a circular cladding was fabricated through an approach that combines an extrusion technique and a multiple-stage rod-in-tube method. This fiber has a Ge 12 As 24 Se 64 glass core with a size of ~2.8 μm × 5.9 μm, and a Ge 10 As 24 S 66 glass cladding with a diameter of ~220 μm, and shows a relatively large birefringence. When ~10 cm long fiber was pumped at 4.0 μm with 330 fs pulses, ~2.2–9.5 μm supercontinuum with a flatness of 20 dB and a polarization extinction ratio of ~10 dB was generated. • A chalcogenide glass fiber with a rectangular core is designed. • The fiber is fabricated by an extrusion technique and a rod-in-tube method. • The fiber shows a background loss of about 3.1 dB/m in the mid-infrared. • Polarized ~2.2–9.5 μm supercontinuum is generated in the fiber. [ABSTRACT FROM AUTHOR]

We report a new Dy3+-doped Ga 2 S 3 -Sb 2 S 3 -La 2 S 3 (GSLS) chalcogenide glass for mid-infrared (mid-IR) laser applications. With the addition of La 2 S 3 into the previously studied Ga 2 S 3 -Sb 2 S 3 glass, the thermal stability of the base glass is significantly enhanced. The glass with the composition 20Ga 2 S 3 -75Sb 2 S 3 -5La 2 S 3 (mol.%) shows the best thermal stability for fiber drawing, and the glass can be doped with up to 5 mol.% Dy 2 S 3. The Dy3+-doped GSLS bulk glasses and a multimode fiber exhibit intense emissions at 2.95 μm and 4.40 μm. Spectroscopic analyses show that the mid-IR emissions are with high quantum efficiencies and large stimulated emission cross sections, indicating that Dy3+-doped GSLS glass is a promising candidate for mid-IR fiber laser medium. • A new chalcogenide glass system Ga 2 S 3 -Sb 2 S 3 -La 2 S 3 (GSLS) is developed. • A core/cladding fiber based on Dy3+-doped GSLS glass is fabricated. • The 20Ga 2 S 3 -75Sb 2 S 3 -5La 2 S 3 glass has the best thermal stability. • The Dy3+-doped GSLS glass and fiber show intense mid-infrared emissions. • Fabricated fiber has a background loss of <3 dB/m in the 2–8 μm spectral range. [ABSTRACT FROM AUTHOR]