Fig. 1. (a) Schematic of Alexandrite laser single-end-pumped by a 532 nm solid-state laser. (b) Schematic of Alexandrite laser single-end-pumped by a 638 nm LDs. M1-M2, high reflection mirrors; HWP, half-wave plate; RM, rear mirror; OC, output coupler; L1-L5, convex lenses; BC, beam collector; TFP, thin film polarizer

Fig. 2. Output powers versus absorbed pump powers of the Alexandrite lasers single-end-pumped by 532 nm solid-state laser and 638 nm LDs

Fig. 3. Schematic of Alexandrite laser double-end-pumped by a fiber-coupled 638 nm LDs. M3-M5, high reflection mirrors; Lb-Lc, convex lenses; TM, turning mirror

Fig. 4. Output powers of the Alexandrite lasers dual-end-pumped by 638 nm LDs with different transmittance of OCs

Fig. 5. Laser wavelength for the Alexandrite laser at output power of 6.2 W with T_OC of 3%

Fig. 6. The M² fit curve of Alexandrite laser with the cavity length of 68 mm and Toc of 3%, the output power of 5.0 W. The inset shows the spatial mode profile of M²<1.47 at output power of 5.0 W