Neodymium-Activated Lanthanum Oxysulfide: A New High-Gain Laser Material

We have observed lasing action at 1.075 μ for Nd in La2O2S (LOS). We have measured the lasing transition cross section of LOS: Nd to be σπ=(2.1±0.2)×10−18 cm2 and that of Nd in Y3Al5O12(YAG) to be σ=(5.6±0.6)×10−19 cm2. The stronger pump bands plus the larger lasing cross section for Nd in LOS relative to YAG result in a lower threshold in both pulsed and cw operation. We obtained sufficient data to predict a cw slope efficiency for LOS:Nd 8–12 times greater than YAG:Nd when LOS crystals with an optical quality comparable to YAG become available.