NEW CW LASER LINES IN THE ER-YALO3 CRYSTAL

We have achieved cw laser action on the 4S3/2→4I9/2 transition of 1.25 at% Er-ions in a YA1O3 host crystal at room temperature. The observed wavelengths are 1.6632, 16776, 1.7061, and 1.7296 μm. The lasing threshold shows a strong temperature dependence, reducing the threshold by more than 50% when the laser rod is cooled from 300 K to 250 K. The influence of the temperature dependent ion-lattice coupling is effective not only in low lying relaxation processes but also in excited state absorption as indicated by fluorescence spectroscopy. © 1990.