Glass doped with PbS quantum dots as a saturable absorber for 1-mu m neodymium lasers

Saturable-absorber mode locking and Q switching of neodymium-doped lasers at 1.06 mum with a PbS-doped glass were demonstrated. Q-switched pulses of 0.3 muJ in energy and 15 ns in duration from a cw diode-pumped Nd3+:KGd(WO4)(2) laser and ultrashort pulses of 18 muJ in energy and 70 ps in duration from a Nd3+:Y3Al5O12 laser were obtained. The saturation intensity of the PbS-doped glass (with an average semiconductor crystallite radius of 1.7 nm) was estimated to be 2.3 MW/cm(2) at 1.06 mum. The bleaching relaxation time was measured to be 23 ps. (C) 2002 Optical Society of America.