Abstract

The effects of ion-ion interactions in heavily doped Er:YAG, Er,Nd:YAG, and Er,Nd;YALO on the lifetimes of the ⁴/_11/2 and ⁴/_13/2 levels of Er³⁺ were studied. In Er:YAG, the ⁴/_13/2 lifetime first increases with increasing concentration and then decreases. The increase can be attributed to radiation trapping and the decrease to concentration quenching. In Nd(1 %), Er(15%):YAG, the ⁴/_11/2 level lifetime is halved, while the ⁴/_13/2 level lifetime suffers an approximately sixty-fold reduction, but τ_13/2 > τ_11/2. However, study of a YALO crystal (1% Nd, 15% Er) disclosed a τ_11/2/τ_13/2 ratio of ≈ 1.7, indicating the feasibility of four-level laser operation. Ion-ion interaction coefficients were obtained from an analysis using the rate equation model. Laser operation at 2900 nm with Nd,Er:YAG, and Nd,Er:YALO is presented.

© 1988 Optical Society of America