Fig. 1. The cavity structure diagram of the single-frequency 1064 nm laser

Fig. 2. Physical conditions for single-frequency operation of the laser. In the figure, "SLM" represents the single longitudinal mode operation, while "MLM" denotes the multi-longitudinal mode operation

Fig. 3. The longitudinal-mode structure of the 1064 nm laser. (a) Without LBO; (b) With LBO

Fig. 4. Variation of laser output power with temperature

Fig. 5. Output power curve of the 50.3 W laser as a function of incident pump power. (Inset: Power stability over a 5-hour duration)

Fig. 6. (a) The beam shape and the M² beam quality of the laser; (b) The longitudinal mode characteristics of the laser

Fig. 7. Schematic diagram of the 101 W laser resonator

Fig. 8. The curve of output power, the beam shape and the M² parameters of the 101 W laser

Fig. 9. The long-tern power stability over 8 hours and the longitudinal-mode structure of the laser

Fig. 10. The linewidth of the laser and its Gaussian fits

Fig. 11. The structure schematic of the 140 W laser cavity

Fig. 12. Theoretical predictions of the mode size variations at the positions of the four laser crystals dependence on incident pump powers (P₁, P₂, P₃, P₄). (a) and (b) Incident pump powers of four laser crystals are synchronously increased; (c) and (d) Increasing the incident power of P₃ and P₄ when P₁ and P₂ are fixed at 70 W, 83 W, 90 W, 103 W and 110 W; (e) and (f) Increasing the incident power of P₁ and P₂ when P₃ and P₄ are fixed at 70 W, 83 W, 90 W, 103 W and 110 W

Fig. 13. The output power curve of the laser under different pumping scheme

Fig. 14. Measured output performances of 1064 nm laser. (a) The stability of output power over 5 h (Insert: Longitudinal-mode structure); (b) Transverse mode structure characteristic; (c) Linewidth; (d) Relative intensity noise spectrum