We investigate the parasitic lasing effect in the high-power actively Q-switched laser with a flat-flat resonator. The parasitic lasing effect in the low-Q stage is found to lead to long tails in the output pulses, corresponding to the peak-power reduction. We experimentally determine the shortest cavity length without the parasitic lasing effect to optimize the performance of the high-power actively Q-switched laser with a flat-flat cavity. We further use the optimized fundamental laser to generate green and UV lasers by extra-cavity harmonic generations. At a pump power of 44 W, the output powers at 355 nm and 532 nm as high as 6.65 W and 8.38 W are obtained at a pulse repetition rate of 40 kHz.
- Acousto-optically Q-switching
- Diode-pumped solid-state laser
- Extra-cavity second and third harmonic generation
- Parasitic lasing effect