Fig. 1. Schematic of the experimental setup （LD：Laser diode; PBS：Polarizing beam splitter；λ/4: Quarter-wave plate; λ/2: Half-wave plate; ISO：Optical isolator）

Fig. 2. Experimental results of oscillator. (a) Output power and pulse width change curve with pulse pump power; (b) Beam quality, inset: Two-dimensional beam intensity distribution profile; (c) Pulse profile, inset: Repetition rate; (d) Spectrum profile

Fig. 3. Output power change curve with pump power. (a) Primary amplifier; (b) Secondary amplifier; (c) Third-stage amplifier

Fig. 4. Beam quality and two-dimensional beam intensity distribution. (a) Primary amplifier; (b) Secondary amplifier; (c) Third-stage amplifier

Fig. 5. Under different cavity lengths, optical parametric oscillator output power and pulse width change curve with pulse pump power. (a) Pump spot diameter is 500 μm; (b) Pump spot diameter is 430 μm

Fig. 6. Output signal characteristics of the optical parametric oscillator. (a) Beam quality, inset: two-dimensional beam intensity distribution; (b) Pulse profile; (c) Spectrum profile