Passive Q-switching of an Er, Yb:glass laser with Co:Mg(Al,Ga)O-based glass-ceramics.

Transparent glass-ceramics (GCs) containing Co:Mg(Al,Ga)O nanocrystals (mean diameter of 7-9 nm) are synthesized by heat treatments at 850-950°C from magnesium aluminosilicate glass nucleated by TiO and doped with GaO and CoO. The GCs exhibit a broadband A4(F4)→T4(F4) absorption due to the Co ions, low saturation fluence (∼0.5  J/cm), fast recovery time of initial absorption (∼300  ns), and high laser damage threshold (∼20  J/cm). They are used for passive Q-switching of a diode side-pumped Er,Yb:glass laser generating 3.1 mJ/20 ns pulses (peak power, 155 kW) at 1535 nm with a TEM output mode. The Q-switching performance of the Co:Mg(Al,Ga)O-based GCs is compared with that for various Co-doped GCs and Co:MgAlO single crystal. The prepared GCs are promising for further applications in passively Q-switched Er:YAG and other Er crystalline (or ceramic) lasers.