Preparation and optical properties of TeO2–BaO–ZnO–ZnF2 fluoro-tellurite glass for mid-infrared fiber Raman laser applications

Abstract

A serial of novel fluoro-tellurite glasses with compositions of 60TeO2–20BaO–(20-x)ZnO–xZnF2 (x = 0, 2, 4, 5 and 6 mol%) were prepared. The compositional dependences of glass structural evaluation, Raman gain coefficient, UV–Vis transmission spectrum, IR transmission spectrum, linear refractive index and third-order nonlinearity were analyzed. The results showed that the addition of 6 mol% ZnF2 can further improve the Raman gain coefficient to as well as 52 × 10−11 cm/W and effectively decrease around 73% and 57% absorption coefficients respectively caused by free OH groups (@3.3 μm) and hydrogen-bonded OH groups (@4.5 μm) in glass. Addition of ZnF2 does not change the UV–Vis absorption edge, optical band gap energy and infrared region cut-off edge almost, while the linear refraction index and ultrafast third-nonlinearity show unmonotonic changes. These novel fluoro-tellurite glasses may be suitable candidates for using in mid-infrared Raman fiber laser and/or amplifier.