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We report on the first diode-laser (nominal 200-mW 10-stripe laser diode) end-pump lasing of Nd:YVO4. The lowest threshold (30 mW) and highest output power (120 mW) were observed from the Nd:YVO4 laser as compared to a similar Nd:YAG laser. Over 50% optical slope efficiency was obtained, the highest yet reported for diode pumping. This device performed at a 10% overall efficiency. Measurements over a 21-nm range show the advantages of the Nd:YVO4 pump absorption band.

The stimulated-emission cross sections at 1064 4I Il/2 ) and 1342 nm (4F3/2-;4I13/2) in Nd : YVO. were determined by measurement of laser thresholds as a fUnction of output mirror reflectivity. Small samples of Nd: YV0 4 and Nd: YAG were end pumped at room temperature with a cw 514.5-nm argon ion laser in an almost identical geometrical arrangement which permitted comparative values to be obtained. Assuming that the pumping quantum efficiency of Nd: YVO is similar to that of Nd: Y AG, the stimulatedemission cross sections obtained for the 1064-and 1342-nm transitions were respectively 12X 10-19 and 6.0X 10-19 cm 2 • PACS numbers: 42.55.Rz

Passive Q switching of Er:glass (1.53 microm) with a new, robust, solid-state saturable absorber, Co(2+):Y(3)Sc(2)Ga(3)O(12), has been demonstrated. Q-switched pulses of 20 ns and 4 mJ of energy were obtained. An absorption cross section of 5 x 10(-20) cm(2) was measured. Preliminary results for a Co(2+):Y(3)Al(5)O(12) saturable absorber Q switch are also discussed.

The materials, Co2+:ZnS and Co2+:ZnSe, serving as Q switches with an Er3+: glass laser at 1.54 μm have been demonstrated and analyzed. The output pulses were typically 15–65 ns in duration and of 1–4 mJ depending on the doping concentration and the crystal quality. The ground-state absorption cross section of Co:ZnS has been determined to be 7.7×10−19 cm2 and 7.6×10−19 cm2 for Co:ZnSe, by bleaching experiments.