Fig. 1. Diagram of laser operating mechanism of energy level structure in Er, Yb∶YAB crystal

Fig. 2. Transmission spectrum of Co²⁺∶MgAl₂O₄ crystal, and experimental setup for passively Q-switched a-cut Er, Yb∶YAB microchip laser. (a) Transmission spectrum of Co²⁺∶MgAl₂O₄ crystal; (b) experimental setup for passively Q-switched a-cut Er, Yb∶YAB microchip laser

Fig. 3. Experimental performance of microchip laser. (a) Average output power and single pulse energy; (b) repetition rate and pulse duration

Fig. 4. Results recorded by oscilloscope for incident power of 7.2 W. (a) Pulse train and pulse repetition rate; (b) single pulse profile and pulse duration

Fig. 5. Test result of pulse laser polarization, and 2D and 3D images of pulse output spots. (a) Test result of pulse laser polarization; (b) 2D and 3D images of pulse output spots