Fig. 1. Schematic of passively Q-switched VECSELs. (a) Cr⁴⁺∶YAG passively Q-switched VECSEL; (b) SESAM passively Q-switched VECSEL

Fig. 2. Photoluminescence of the gain chip under 1.2 W pump power and laser spectrum of VECSEL under 5.6 W pump power at room temperature

Fig. 3. Relationship between output power of continuously running VECSEL and pump power at room temperature

Fig. 4. M² factor of laser beam when output power is 924 mW (inset is three-dimensional diagram of light intensity distribution)

Fig. 5. Pulse waveform of Cr⁴⁺∶YAG passively Q-switched VECSEL with 4.5 W pump power at room temperature

Fig. 6. Pulse waveform of the SESAM passively Q-switched VECSEL with 4.5 W pump power and room temperature

Fig. 7. Relationship between pulse periods of the SESAM passively Q-switched VECSEL and pump power

Fig. 8. Output power varies with pump power of the SESAM passively Q-switched VECSEL at room temperature