  We report on a laser source at 589 nm based on sum-frequency generation of
two infrared laser at 1064 nm and 1319 nm. Output power as high as 800 mW are
achieved starting from 370 mW at 1319 nm and 770 mW at 1064 nm, corresponding
to converting roughly 90% of the 1319 nm photons entering the cavity. The power
and frequency stability of this source are ideally suited for cooling and
trapping of sodium atoms.
