Fig. 1. Orthogonal layout of pumping source, laser, and flow field in direct-liquid-cooled thin-disk laser

Fig. 2. Convective heat transfer coefficient hc and pressure drop P versus flow velocity in micro-channel

Fig. 3. Design limit for maximum heat generation

Fig. 4. s-polarization light distribution for gain medium after thermal depolarization

Fig. 5. Single disk loss versus Brewster angle deviation

Fig. 6. Single disk loss introduced by thermo-optic effect

Fig. 7. Round-trip loss versus number of disks

Fig. 8. Output power versus number of disks at different loss of single disks

Fig. 9. Output power and optical-to-optical conversion efficiency

Fig. 10. Thermal aberration under side-pumping

Fig. 11. Influence and compensation of intra-cavity cylindrical defocus

Fig. 12. Thermal aberration caused by cooling flow field and tilt self-compensation. (a) Intra-cavity aberration distribution under same flow direction; (b) schematic of tilt self-compensation; (c) intra-cavity aberration distribution under opposite flow direction

Fig. 13. Legendre polynomial expansion of phase aberration

Fig. 14. Typical distributions of temperature and fOPD due to laser absorption by liquid. (a) Temperature distribution of liquid with a single layer. (b) fOPD of liquid with 20 layers

Fig. 15. Effect of fOPD due to laser absorption by liquid on transient variation of laser beam quality

Fig. 16. Experiment device of direct-liquid-cooled thin-disk solid-state laser. (a) Design diagram; (b) output picture of the laser system

Fig. 17. Output single pulse energy and optical-to-optical conversion efficiency

Fig. 18. Average output power characteristics under different pumping powers