Passively Q-switched Tm:YLF laser.

Stable passive Q-switching of a Tm:  LiYF4 laser is obtained using polycrystalline Cr2+:  ZnS as a saturable absorber. The achieved maximum pulse energy of 0.9 mJ and peak power of 65 kW for a pulse duration of ∼14  ns represent substantial improvement and highest values for a passively Q-switched diode-pumped Tm laser operating at ∼1.9  μm.