Abstract：A cw operation and a passively Q-switched (PQS) Ho:SSO laser (Cr$^{2+}$:ZnSe as a saturable absorber) end-pumped by a Tm:YAP laser operating at near room temperature are reported. It is the first time to report a PQS Ho:SSO laser. For the cw mode, a maximum cw output power of 3.0 W is obtained, corresponding to a slope efficiency of 31.4%. For the PQS mode, a Cr$^{2+}$:ZnSe is used as the saturable absorber, with transmission of 88.4% at 2112 nm. A maximum pulse energy of 1.29 mJ is obtained, corresponding to the pulse repetition frequency of 2.42 kHz. In this study, we change the distance between Cr$^{2+}$:ZnSe and the output mirror to research the pulse characteristic of the PQS Ho:SSO laser. The minimum pulse width of 73.5 ns is obtained, corresponding to the pulse energy of 0.9 mJ and the pulse repetition frequency of 2.65 kHz.
2017, Vol. 34 
