33 W quasi-continuous-wave narrow-band sodium D2a laser by sum-frequency generation in LBO

We demonstrate an all-solid quasi-continuous-wave(QCW) narrow-band source tunable to sodium D2 aline at589.159 nm. The source is based on sum-frequency mixing between lasers at 1064 nm and 1319 nm in a LBO crystal.The 1064 nm and 1319 nm lasers are produced from two diode side-pumped Nd:YAG master oscillator power amplifier(MOPA) laser systems, respectively. A 33 W output of 589 nm laser is obtained with beam quality factor M2= 1.25,frequency stability better than ±0.2 GHz and linewidth less than 0.44 GHz. A prototype 589 nm laser system is assembled,and a sodium laser guided star has been successfully observed in the field test.