Design and field tests of an 8-W sum-frequency laser for adaptive optics

The design and characteristics of an 8 watt diode laser pumped version of the sum frequency laser designed for astronomy is described together with an outline of field test undertaken on the NOAO Vacuum Telescope Tower at Sac Peak. Optical pumping effects were shown to increase the return by a factor of 2.5 subarcsecond beacons were produces with a brightness equal to a 9.2 magnitude star with 1.2 watts incident at the sodium layer under sodium abundance column density of 5 X 109 atoms/cm2.