Fig. 1. Schematic of laser configuration

Fig. 2. Schematic of slab gain medium

Fig. 3. Power distributions of two slabs at different positions for the case of amplifying for two pass and then connecting two slabs in series. (a) Slab 1; (b) slab 2

Fig. 4. Power distributions of two slabs at different positions for the case of connecting two slabs in series and then amplifying for two pass. (a) Slab 1; (b) slab 2

Fig. 5. Output power as a function of pump power

Fig. 6. Photo when laser system is running

Fig. 7. Pulse width of output laser

Fig. 8. Space characteristics of wavefront distortion of output laser at output power of 4256 W. (a) Distortion of wavefront; (b) far-field spot