Growth and Efficient 1 μm Laser Operation of Yb-Doped Mixed Sesquioxides

Cubic sesquioxides are known to exhibit a high thermal conductivity, allowing for efficient heat removal even at high laser output powers. Their relatively low phonon energies inhibit non-radiative decay processes relevant for near and mid-infrared lasers. Sesquioxide crystals doped with
$\text{Ho}^{3+}, \text{Er}^{3+}, \text{Tm}^{3+}$
or
$\text{Yb}^{3+}$
enabled highly efficient laser performance in continuous wave (CW) and mode-locked laser operation [1].
$\text{Yb}^{3+}$
-doped
$\text{Lu}_{2}\mathrm{O}_{3}$
is an ideal material for high-power thin-disk lasers in multimode CW operation [2] and enables the generation of ultrashort pulses at high average power levels [3]. However, its growth is challenging due to the high melting temperature of more than
$2400^{\circ}\mathrm{C}$
. As a result, high-quality sesquioxide crystals are not commercially available to date, despite successful growth results using the heat exchanger method (HEM) in the past [4].