8 μm luminescence from a Tb3+ GaGeSbSe fiber

In this Letter, we report for the first time, to the best of our knowledge, on an emission at 8 mu m from Tb3+-doped Ga5Ge20Sb10Se65 chalcogenide fibers with doping levels at 1000 ppm and 500 ppm. These fibers were drawn following conventional melt-quenching methods and pumped at 2.05 mu m using a Tm3+ : YAG laser. The spectroscopic properties of the emitting F-7(4) manifold are investigated to rule out any parasitic signal mimicking the real Tb3+ 8 mu m emission. Time-resolved spectroscopic experiments are presented to build a comprehensive study of this 8 mu m fluorescence recorded with a clear signal-to-noise ratio. (c) 2018 Optical Society of America