Fig. 1. Experimental configuration of the SESAM mode-locked Yb:KGW laser. LD, laser diode; Yb:KGW, Yb:KG(WO₄)₂; SESAM, semiconductor saturable absorber mirror; DM, dichroic mirror; HR, high reflection mirror; M1, M2, M3, concave mirrors (R = 500 mm, 300 mm, 500 mm, respectively); OC, output coupler; GTI, Gires–Tournois interferometer mirror.

Fig. 2. (a) Output power as a function of the pump power. The blue solid line has a slope efficiency of 64.4%. (b) Power fluctuations at 13 W average output power in 2 h.

Fig. 3. Spectral distribution of Yb:KGW mode-locked laser at the average output power of 13 W.

Fig. 4. Measured intensity autocorrelation trace of Yb:KGW femtosecond laser at the central wavelength of 1039 nm.

Fig. 5. Typical RF with an RBW of 1 kHz. Inset: RF spectrum at 1 GHz wide span with the RBW of 200 kHz.

Fig. 6. Measured beam quality factor M² of Yb:KGW femtosecond oscillator at the 13 W average output power.