Enhanced ∼2 μm Emission of Tm³⁺ in Lu₂O₃ by Addition of a Trace Amount of Er³⁺

Abstract

Er-induced intensity enhancement of ∼2 μm emission is observed in 2 atom % Tm doped LuO under 782 nm excitation. The maximum enhancement reaches 41.9% with only 0.05 atom % Er. Er introduces a new quantum cutting process which is proved to be a Tm → Er → Tm forward-backward energy transfer (FBET) system. The FBET system is observed to work efficiently even at very low Er concentration. Thus, energy loss due to energy migration among Tm ions is suggested to be suppressed by the FBET process. The Tm → Er → Tm FBET system may be a new route to improve the performance of Tm lasers.