Influence of Codopant Ions on the Fluorescence Decay Characteristics of Er:YSGG

The 3 um erbium laser has been the subject of severa1 investigations in recent years to improve the laser performance. They ranged from using new host crystals to adding codopant ions in an effort to eliminate the self-terminating behaviour of the (4111/2 -4113/2) lasing transition. Codoped Er:YAG with Nd [1] was not successful in reversing the lifetime ratios while the same codoped system in a YALO host [2] led to lower state lifetime shorter than the upper state, but the latter was significantly quenched. CW operation of this lasing transition was reported in a diode-pumped Er:YLF laser [3] as well as a krypton ion pumped Er:YSGG laser [4]. No codopant was used and a nonlinear quenching mechanism that depopulates the metastable 4113/2 state under high excitation condition is believed to be responsible for the cw operation. Huber et al [4] also found that codoped Er:YSGG with Ho gave better slope efficiency.