We report a 10 mW threshold miniature device in which internalQ-switching of a single Nd:MgO:LiNbO3crystal is achieved. Pulsewidths of 30 ns have been observed. Peak powers of 5 W have been attained with less than 60 mW of 598 nm pump power and with less than 1 percent output coupling. The switching voltage is lower than 300 V. The consequences of the elastooptic effect and the photoconductivity on device performance are investigated. A highly efficient CW laser and a low threshold CW laser made of the same material are also reported. Photorefractive damage due to the photovoltaic effect is found to be almost nonexistent in these lasers when pumped in the near-infrared.