Diode-Pumped Kerr-Lens Mode-Locked Yb:YAl3(BO3)4 Laser

Ytterbium $(\text{Yb}^{3+})$ doped trigonal yttrium aluminum borate, $\text{Yb}^{3+}:\text{YAl}_{3}(\text{BO}_{3})$ , (abbreviated Yb:YAB), represents a well-known structurally ordered laser crystal which is very suitable for the development of high-power lasers both in the continuous-wave and Q-switched regimes at ~1μm [1]. It is an optically uniaxial (negative) crystal with non-centrosymmetric huntite-like structure (sp. gr. $R32$ , point group 32) exhibiting high nonlinearity ( $d_{\text{eff}} > 1.4$ pm/V [2]), being recognized as one of the most promising self-frequency doubling (SFD) laser crystals for generating coherent radiation in the visible spectral range [3]. The relatively broad and flat gain spectra of the $\text{Yb}^{3+}$ ions in YAB support sub-100 fs pulse generation from passively mode-locked (ML) lasers [4], [5]. In combination with its relatively good thermal conductivity ( $4.7\ \text{Wm}^{-1}\mathrm{K}^{-1}$ for 5.6 at% Yb doping [6]), as well as broad gain profiles, the Yb:YAB crystal has good potential for the power scalable operation of femtosecond lasers at ~1 μm [7]. In the present work, we report on a diode-pumped Yb:YAB laser delivering soliton pulses as short as 36 fs at 1059.7 nm with an average output power of 156 mW via Kerr-lens mode-locking (KLM).