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).