Fig. 1. Configuration of the direct-liquid-cooled distributed-reflective-type laser MOPA system

Fig. 2. Sketch of the Zig-Zag similar-like path in the gain medium array

Fig. 3. Sketch of laser path deviation

Fig. 4. Sketch of Brewster angle transmission between gain media and pupil self-compensation laser path

Fig. 5. Proportion of pump absorption and doping concentration for each Nd∶YAG crystal in a gain module

Fig. 6. Schematic diagram of a gain medium in the direct-liquid-cooled distributed-reflective-type laser gain module

Fig. 7. Theoretical gain distribution in the gain module during laser extraction

Fig. 8. Theoretic input and output curves of the direct-liquid-cooled distributed-reflective-type laser gain module. (a) Output optical-optical (O-O) efficiency; (b) output power

Fig. 9. Output feature of the magnified system varies with the interface loss

Fig. 10. Flow channel design diagram of the distributed-reflective-type laser gain module

Fig. 11. Temperature distribution of the gain medium, where the curve is the temperature distribution of the gain medium along the thickness direction, and the inset shows the temperature distribution of the gain mediuim along the flow direction

Fig. 12. Theoretic thermal-induced wavefront and far-field distribution of the laser output. (a) Thermal-induced wavefront of the laser after passing through two modules; (b) the corresponding far-field distribution

Fig. 13. Experimental setup of the direct-liquid-cooled distributed-reflective-type laser MOPA system

Fig. 14. Detail of the direct-liquid-cooled distributed-reflective-type laser gain module

Fig. 15. Output power and O-O efficiency of the direct-liquid-cooled distributed-reflective-type laser magnification verification device, where the inset shows the variation of laser output power with time

Fig. 16. Temporal profile of the direct-liquid-cooled distributed-reflective-type laser magnification verification device, where the inset shows the pulse series of the output laser

Fig. 17. Extracted power and O-O efficiency of the two magnified modules in the direct-liquid-cooled distributed-reflective-type laser magnification system. (a) Extracted power; (b) O-O efficiency

Fig. 18. Beam quality of the direct-liquid-cooled distributed-reflective-type laser magnification system. (a) Two-dimensional far-field distribution; (b) three-dimensional far-field distribution; (c) wavefront residual of the output laser; (d) near-field of the output spot