946-nm Nd:YAG laser under direct diode-pumping at 869 nm

We present investigations on resonant pumping at 869 nm into the upper laser level of end-pumped Nd:YAG lasers operating on the /sup 4/F/sub 3/2//spl rarr//sup 4/I/sub 9/2/ transition at 946 nm. We used a 5 mm long Nd:YAG crystal with a doping level of 0.7 at% and measured the absorption of the diode laser light at 869 nm. We set up a pump optics with two AR-coated plano-convex aspherical lenses and a two-mirror-cavity with a plane in-coupling mirror. This mirror gave a small fundamental laser mode size with lower threshold and higher output power.