Spectroscopic Properties of Holmium-Aluminum- Germanium Co-doped Silica Fiber

2020

We report the basic spectroscopic properties of a home-made holmium-aluminum-germanium co-doped silica fiber, designed for laser applications. We present the ground-state and excitedstate absorption spectra of the fiber along with the upconversion emission spectrum under laser action, which served for making an energy levels’ diagram of Ho3+ ion. We discuss the ways to assess the kinetics of Ho3+ 2-μm fluorescence, focusing on measuring fluorescence lifetime from 5I7 level and nonradiative decay time from 5I6 level. The simple analytical formulae, applicable for fitting of the fluorescence decay curve, are derived, which can be useful for precise modeling of holmiumdoped fiber lasers. PID20…