THERMAL EFFECTS ON THE QUANTUM EFFICIENCY OF 3 MU-M ERBIUM LASERS

The temperature dependence of the main energy transfer processes invol ved in the building of population inversion in 3 mu m Erbium lasers, m ainly upconversion from I-4(13/2), I-4(11/2), and cross-relaxation fro m I-4(9/2), is investigated In the temperature domain 20-100 degrees C , which includes the usual working temperatures of solid-state lasers, the change of the quantum efficiency is mainly due to the modificatio ns of the Stark sublevels populations involved in laser transitions. T he contribution of the cross-relaxation from I-4(9/2) is estimated usi ng new experimental data for two Erbium-doped crystals: Er3+:YAlO3 and Er3+:YLiF4.