Fig. 1. Principle diagram of Er∶YAG single-frequency pulsed laser system

Fig. 2. Simulated pulse waveforms under different conditions. (a) Different injection seed powers;(b) different frequency detunings

Fig. 3. Simulation results of relationship between coupling coefficient and ω₂₀

Fig. 4. Characteristics of energy and pulse duration as well as waveform diagram of single-frequency pulse. (a) Output pulse energy and pulse duration versus incident pump power at repetition frequency of 200 Hz; (b) waveform diagram of single-frequency pulse with maximum output energy

Fig. 5. Test results of heterodyne beat frequency. (a) Heterodyne beat signal; (b) spectrum of heterodyne beat signal

Fig. 6. Stability test results within 30 min for single-frequency pulse with the highest output energy. (a) Energy stability;(b) frequency stability

Fig. 7. Laser beam quality in injection locking mode