A cobalt-doped transparent glass ceramic saturable absorber Q-switch for a LD pumped Yb3+/Er3+ glass microchip laser

We fabricate a transparent glass ceramic contains magnesium-aluminum spinel nanocrystallites doped with Co 2+ ions. The ground-state and excited-state absorption cross section of this glass ceramic at 1.54 μm are estimated to be (2.8 ± 0.3) × 10 −19 cm 2 and (4.8 ± 0.5) × 10 −20 cm 2 , respectively. For the first time, the passively Q-swithched operation of LD pumped 1.54 μm microchip Yb 3+ /Er 3+ glass laser is realized with transparent glass ceramic as saturable absorber. The Q-switched pulses of 3.846 kHz in repetition rate, 6.2 ns in duration and 6.3 μJ in energy are obtained. At last, the dependences of pulse width and repetition rate on pump power are also investigated.