Soliton mode-locking and nonlinearity characterization of Yb3+:Y2SiO5 crystal

An efficient soliton mode-locking femtosecond Yb3 + : Y2SiO5 (Yb:YSO) laser at 1059 nm assisted with semiconductor saturable absorber mirror has been successfully realized and demonstrated. Nearly Fourier transform-limited pulse duration as short as 236 fs has been achieved with a pulse repetition frequency of 79.6 MHz and an average output power of 903 mW, corresponding to maximum pulse energy of 11.34 nJ and pulse peak power of 48 kW, respectively. The dependence of pulse duration on the intracavity pulse energy in soliton mode-locking regime has been further investigated and discussed, which is fitted by the soliton mode-locking theory and indicates the nonlinear refractive index n2 of the Yb:YSO crystal to be around 2.1 to 4.8 × 10 − 16 cm2 / W.