Co2+:LaMgAl11O19 saturable absorber Q-switch for a 1.319 μm Nd3+:YAG laser

Passively Q-switched output of a flashlamp-pumped 1.319 μm Nd:YAG laser is realized by using Co2+:LaMgAl11O19 (Co:LMA) as saturable absorber. When initial transmission of the saturable absorber T0 is 78%, a Q-switched output pulse with pulse width (FWHM) 44.8 ns and pulse energy 17.4 mJ is obtained, corresponding to ∼19.3% of the free-running energy under the equal pumping energy of 45.4 J. The experimental results show that the higher T0 will result in a lower pumping threshold of the laser, but lower T0 can make the laser generate pulses with higher single-pulse energy, narrower pulse width, and accordingly higher peak power.