Fig. 1. Level diagram of Yb3+ ion and distribution of Stark energy sub-levels

Fig. 2. Wavelength-dependent absorption and emission cross sections of Yb∶YAG

Fig. 3. Experimental setup of Yb∶YAG slab amplifier

Fig. 4. Normalized spectra of (a) seed and (b) pump light

Fig. 5. Comparison of numerical simulation and experimental results of laser output spectrum under different pump powers. (a) Pump power is 9981 W; (b) pump power is 13401 W; (c) pump power is 16789 W; (d) pump power is 20001 W

Fig. 6. Experimental results of output power and optical to optical efficiency