Preparation and properties of Ga2S3-Sb2S3-Ag2S chalcogenide glasses and fibers

With the rapid development of infrared technology and the wide applications of infrared opticalcomponents, the demand for infrared optical materials has risen significantly. Chalcogenide glass has beenconsidered as one of the most popular infrared optical materials because of its wide infrared transmission range,high refractive index, low phonon energy, good rheological properties, low cost, etc. In this work, a new type ofGa(2)S(3)-Sb2S3-Ag2S chalcogenide glass system is reported, and its glass forming domain is determined. Thethermal stability and optical property, mid-infrared (MIR) emission of rare earth dopant, and fiber-formingproperty for the glasses are studied. The potential applications of the glasses in the MIR region are alsoevaluated. The experimental results show that the Ga2S3-Sb2S3-Ag2S system has a glass forming domain of similar to 10%-30% Ga2S3, similar to 60%-80% Sb2S3 and similar to 0-15% Ag2S (all in molar percentage). These glasses have a wideinfrared transmission range of similar to 0.8-13.5 mu m, relatively high linear refractive indices of similar to 2.564-2.713 (at 10 mu m),and relatviely large third-order nonlinear refractive indices of similar to 9.7x10(-14)-15.7x10(-14) cm(2)/W (at 1.55 mu m). Theseexcellent properties make the Ga2S3-Sb2S3-Ag2S glass promising material in the fields of infrared thermalimaging and nonlinear optics. Under the excitation of 1.32 mu m laser, the rare earth dopant Dy3+ shows strong2.91 mu m and 4.41 mu m MIR emissions in the glass. According to the J-O theory, the three strength parameters(Omega(2), Omega(4), Omega(6)) of Dy3+ in 0.05% weight of Dy3+ doped 20Ga(2)S(3)-75Sb(2)S(3)-5Ag(2)S glass are 7.38x10(-20) cm(2), 2.24x10(-20)cm(2) and 0.75x10(-20) cm(2), respectively. The quantum efficiencies of the 2.91 mu m and 4.41 mu m emissions arecalculated to be 76.6% and 70.8%, respectively, while the stimulated emission cross sections of those two bandsare 1.27x10(-20) cm(2) and 1.43x10(-20) cm(2), respectively. The fiber based on 20Ga(2)S(3)-75Sb(2)S(3)-5Ag(2)S: 0.05% Dy(3+)core glass and 20Ga(2)S(3)-70Sb(2)S(3)-10Ag(2)S cladding glass is fabricated by rod tube method. The fiber has goodtransmission performance in the 2-8 mu m wavelength range, and the minimum loss is similar to 3.5 dB/m at 5.7 mu m. TheDy(3+) ions show intense 2.93 mu m and 4.45 mu m MIR emissions in the fibers under 1.32 mu m excitation. Theseresults indicate that the Dy3+ doped Ga2S3-Sb2S3-Ag2S glass fiber can be a promising candidate for MIR fiberlaser medium