CW and passively Q-Switched operation of a Ho:YAG waveguide laser

We report the first demonstration of a Ho: YAG crystal fiber waveguide (CFW) laser operating at 2.09 µm. The CFW structure was produced by adhesive free bonding of holmium doped yttrium aluminum garnet core to an undoped yttrium aluminum garnet cladding. The laser produced CW output powers greater than 500 mW with slope efficiency of 17%. The same crystal when passively Q-switched with Cr: ZnSe, produced pulsed output with energies of 1 μJ at a repetition frequency of 442 kHz.