MgAl 2 O 4 saturable absorber

We report, for the first time to our knowledge, efficient passive Q-switching of the 1.54-µm laser transition in an Er-Yb-doped crystalline medium. The laser configura- tion is a compact microchip design that is suitable for a range of practical applications such as range finding and lidar. The slope efficiency of 11.6%, pulse duration of 5-6 ns and aver- age output power of 88 mW are all comparable with standard Er-Yb:glass lasers.