Fig. 1. Schematic of the experimental setup

Fig. 2. Output energy change curve with the pump energy. (a) Oscillator; (b) primary amplifier; (c) secondary amplifier

Fig. 3. Beam quality of the output laser from 1064 nm pump source

Fig. 4. Typical pulse shape of the Nd∶YAG laser system. (a) Oscillator; (b) primary amplifier; (c) secondary amplifier

Fig. 5. Output energies of different OPOs. (a) Output energies under different crystal lengths; (b) output energies under different cavity lengths

Fig. 6. Output energy curve of the KTA-OPO. (a) Energy curve; (b) output stability

Fig. 7. Typical pulse of OPO at maximum output energy. (a) Signal light; (b) idle frequency light

Fig. 8. Beam quality of the signal light

Fig. 9. Spectrum of the signal light