Study on fluorescence characteristics of the Ho 3+ :ZBLAN fiber under ~640 nm excitation

Abstract(#br)We investigated the absorption and emission characteristics of the Ho 3+ :ZBLAN fiber under ~640 nm excitation. Based on the Judd-Ofelt theory, a detailed spectroscopic analysis on excited states 5 I 6 and 5 I 7 of the Ho 3+ -ion was performed. The population dynamics was conducted by using the rate equation method, and a set of analytical expressions for population densities of various levels were obtained at steady state. Moreover, the fluorescence intensities of the 5 S 2 , 5 F 4 → 5 I 7 , 5 I 8 and 5 I 6 → 5 I 7 , 5 I 8 and 5 I 7 → 5 I 8 transitions were measured in different pumping powers. The simulated and experimental results are quite consistent. This work could provide the spectral information for optimal design of the visible oscillations in the Ho 3+ :ZBLAN fiber excited at ~640 nm