Avalanche-like mechanisms and up-conversion processes under infrared pumping in Ho3+, Yb3+:YAlO3

This paper presents an analysis of the green emission of Ho3+ (5S2→5I8) under excitation around 750 and 840 nm in the Ho3+, Yb3+:YAlO3 system. The up-conversion process in the case of pump around 750 nm is a combination between a looping mechanism based on excited state absorption from the 5I7 level and an avalanche mechanism based on excited state absorption from the 5I6 level.