Fig. 1. Working principle diagrams of OPOs with different structures. (a) SRO; (b) DRO

Fig. 2. Experimental setup for extracavity frequency-doubling blue laser output based on OPO pumped by 532 nm

Fig. 3. Stability measurement of pump laser output energy

Fig. 4. Stability measurement of pump laser pulse sequence

Fig. 5. OPO signal light energy and conversion efficiency versus pump light energy with 972 nm spectrum shown in inset

Fig. 6. Stability measurement of 972 nm output energy

Fig. 7. 972 nm pulse waveform with 972 nm near-field spot shown in inset

Fig. 8. Measurement results of beam quality at 972 nm

Fig. 9. Second-harmonic energy and conversion efficiency versus fundamental energy with 486 nm spectrum shown in inset

Fig. 10. 486 nm pulse waveform with near-field spot shown in inset

Fig. 11. Measurement results of beam quality at 486 nm