Growth and Characterization of High-Melting Sesquioxides for 3 μm Lasers

Due to the strong absorption in water, lasers in the wavelength range of 3 μm are attractive in fields like laser surgery or atmospheric detection. To achieve good beam quality and stable high-power laser operation, good mechanical, optical and thermal properties are essential for potential host materials. Rare-earth sesquioxide crystals are very suitable for high-power mid-infrared applications due to their high thermal conductivity and low phonon energies. In 2012 Er-doped lutetia (Lu
₂
O
₃
) was introduced as an efficient 3 μm laser material [1]. Due to its good thermo-mechanical properties, this materials allowed for the highest room-temperature laser power of any Er-doped crystalline host material at the time. Also other cubic sesquioxide host materials such as scandia (Sc
₂
O
₃
) and yttria (Y
₂
O
₃
) are very promising in this respect [2, 3].