Efficient intracavity-pumped Ho:SSO laser with cascaded in-band pumping scheme

In this paper, we have demonstrated an efficient intra-cavity pumped Ho:SSO laser based on a cascaded in-band pumping scheme for the first time. The laser diode at 1.6 µm was used to pump the Tm:YAG crystal. At an incident LD pump power of 18.7 W, dual end-pumped Tm:YAG laser provides the maximum output power of 9.7 W with a slope efficiency of 55.9%. With the same incident LD power, a maximum output power of 4.9 W at 2116.5 nm was achieved with a slope efficiency of 31.6% in the Ho:SSO laser intra-cavity pumped by a Tm:YAG laser. The beam quality factor of the Ho:SSO laser at maximum output level was measured to be 1.1 and 1.2 in the horizontal and vertical directions, respectively.