Sub-40 fs Diode-Pumped SESAM Mode-Locked Yb:Sc2SiO5 Laser

Ytterbium (Yb ³ +) doped rare-earth oxyorthosilicates with a general chemical formula of Yb ${}^{3+}:\text{RE}_{2}\text{SiO}_{5}$ (where RE = Gd [1], Y [2], Lu [3] or Sc [4]), crystallize in the monoclinic system $(\text{sp}.\ \text{gr}.\ C2/c,\ C_{2h}^{6})$ . One of the well-known representatives of this crystal family is the scandium oxyorthosilicate Yb:Sc 2 SiO 5 . It exhibits a relatively high thermal conductivity of 7.5 Wm-1K-1 (for 1 at.% Yb ³ + doping) at room temperature and a negative thermooptic coefficient of $-6.3\times 10^{-6}\mathrm{K}^{-1}$ [5], which ensures good heat removal and a relatively weak thermal lensing effect. The broad gain profiles and the moderate luminescence lifetime (0.7 ms) of Yb:Sc 2 SiO 5 make it very suitable for the development of femtosecond mode-locked (ML) oscillators and amplifiers [6]. Power scalable operation of such oscillators is also possible in the thin-disk architecture. In this work, we demonstrate sub-40 fs soliton pulse generation from a diode-pumped SESAM ML Yb: $\text{Sc}_{2}\text{SiO}_{5}$ laser near 1070 nm.