Nanosecond Pulse Generation at 2.7 μm From a Passively Q-Switched Er:Y2O 3 Ceramic Laser

Efficient passively Q-switched Er:Y
₂
O
₃
ceramic lasers operating at 2.7 
μ
m were demonstrated. Using a semiconductor saturable absorber mirror (SESAM) of 2.4% modulation depth, we achieved 63 ns pulses that are close to the limit set by the cavity length. For 9.5 W of the absorbed pump power, an average output power of 0.88 W was generated with a pulse energy of 17.4 
μ
J and a pulse duration of 63 ns, resulting a pulse peak power of 0.27 kW. By using an SESAM with a lager modulation depth, shorter pulses of 29 ns were generated. To our knowledge, this is the first report of sub-100 ns pulses from the continuously pumped ∼3-
μ
m passively Q-switched lasers. The prospects for further pulse shortening are considered, and these results may give a further insight into 3-
μ
m passively Q-switched laser systems.