A calcium atomic beam has been decelerated by a single extended-cavity diod
e laser, frequency doubled to 423 nm. A potassium niobate crystal is placed
in an external power buildup cavity, and the second-harmonic laser beam, c
ounterpropagating with the atomic beam, is tuned into resonance with the st
rong S-1(0)-P-1(1) transition of calcium. For input power of 78 mW at 846 n
m, we generate 22 mW at 423 nm after correction for the reflectivity of our
cavity output coupler. To keep the atoms always in resonance during the de
celeration process, the Zeeman tuning technique was used. (C) 1999 Optical
Society of America.