Directly Diode-Pumped Ho:YAG Ceramic Laser

We present a Ho
³⁺
-doped YAG ceramic laser which is directly diode-pumped at ~ 1.13 μm for the first time. The Ho:YAG ceramic slab in this letter has a dimension of 4.2 × 4.8 × 22 mm
³
and a doping concentration of 1 at%. The fiber coupled laser diode (LD) used for pumping has central wavelengths of 1.123-1.130 μm and a typical FWHM bandwidth of 5 nm. The efficient absorption of Ho:YAG ceramic is stable for broadband LD pump sources. The maximum output power was up to 1 W of continuous wave at the lasing wavelength of 2099 nm. The laser has a slope efficiency of 20.6% with respect to absorbed power and a beam propagation factor of M
²
~ 4 at the maximum output power.