Fig. 1. Schematic of side-cooled bulk Yb∶YAG laser amplifier

Fig. 2. Structure of Yb∶YAG laser crystal

Fig. 3. Propagation and reflection of ASE beams in triangular-section channel

Fig. 4. Simulation of local ray tracing on side of bulk Yb∶YAG crystal

Fig. 5. Schematic of Yb ion energy level and Stark sublevel

Fig. 6. Energy storage in amplifier at different temperatures and pumping intensities with 1-ms pump pulse duration. (a) Small signal gain coefficient; (b) energy storage efficiency

Fig. 7. Output energy as a function of injection energy of four-pass amplification at optimized temperature

Fig. 8. Temperature distributions of laser crystal. (a) Crystal without triangular-section channels on side; (b) crystal with triangular-section channels on side

Fig. 9. Photo of Yb∶YAG laser amplifier

Fig. 10. Simulation and experimental results of four-pass amplification

Fig. 11. Analysis of far-field spot of amplifier output. (a) Distribution of relative intensity in far field; (b) curve of energy concentration