Fig. 1. Schematic of typical cavity of KLM thin disk laser resonator

Fig. 2. Intracavity mode radius ω on end mirror versus Lf during continuous optical output

Fig. 3. Mode radius of resonator at OC versus fKM when Lf is slightly smaller than l2

Fig. 4. Optical structure diagram and physical diagram of 72-pass pump module^[20]. (a) Optical structure diagram; (b) physical diagram

Fig. 5. Schematic of KLM Yb∶YAG thin disk laser cavity used in experiment

Fig. 6. Comparison of mode radius of cavity with 150 mm RoC focusing mirror during continuous wave operation and mode-locked operation

Fig. 7. Output power and optical-optical efficiency of Yb∶YAG thin disk laser (R150) during continuous wave operation versus pump power

Fig. 8. Mode-locked output femtosecond pulse train of Yb∶YAG thin disk laser (R150) at different oscilloscope sampling time. (a) 0.25 μs; (b) 2.0 μs

Fig. 9. Intensity autocorrelation curve and sech² fitting result of mode-locked output femtosecond pulse of Yb∶YAG thin disk laser (R150)

Fig. 10. Mode-locked output spectrum of Yb∶YAG thin disk laser (R150)

Fig. 11. Output double pulse train of Yb∶YAG thin disk laser（R150）

Fig. 12. Output double pulse spectrum of Yb∶YAG thin disk laser（R150）

Fig. 13. Intensity autocorrelation curve and sech² fitting result of mode-locked output femtosecond pulse of Yb∶YAG thin disk laser (R200)

Fig. 14. Mode-locked output optical spectrum of Yb∶YAG thin disk laser (R200)