High-stability and high-beam-quality single-frequency nanosecond 589 nm laser based on sum-frequency generation

A high repetition rate, high peak power, narrow linewidth nanosecond 589 nm laser based on sum-frequency generation (SFG) of 1064 nm and 1319 nm laser is demonstrated. A 1064 nm single-frequency distributed-feedback laser diode (DFB-LD) externally modulated by an acousto-optic modulator (AOM) and amplified by a fiber-solid hybrid amplifier with three-stage fiber amplifier and six-stage solid-state end-pump Nd:YVO4/Nd:YAG amplifier, a high beam quality laser output with pulse energy of 20 mJ at repetition rate of 500 Hz is achieved, which pulse duration and waveform are adjustable and editable. The ramp–hold–fire detection and dual piezoelectric ceramic (PZT) feedback compensation are employed in the 1319 nm oscillator to achieve high stability and low jitter laser. Then the 1319 nm laser pulse is amplified to 12.2 mJ by three-stage end-pumped Nd:YAG amplifier, with pulse duration of 70 ns. By sum-frequency of the 1064 nm and 1319 nm lasers, finally, 589.1595 nm laser with pulse energy of 10.4 mJ and pulse duration of 62 ns is generated efficiently, the laser beam quality factor M2 is less than 1.3. With the ability of switching frequencies quickly and the characteristic of compatible frequency-stabilized, this laser is believed to be a very potential solution for sodium Doppler lidar.