P-004

Domantas Černius

domantas.cernius@chgf.stud.vu.lt

Monika Skruodienė, Anatolijs Šarakovskis, Ekaterina Pomjakushina, Ramūnas Skaudžius

Department of Inorganic Chemistry, Vilnius University, Lithuania

Growth and Characterization of CALGO:Yb Crystals Using the Optical Floating Zone Method for Laser Applications

The broad and smooth emission bandwidth of ytterbium-doped calcium gadolinium aluminum oxide (CaGdAlO4:Yb; CALGO:Yb) crystals makes them essential for developing high-power and ultrashort pulse laser technologies. CALGO:Yb is a good material because of exceptionally broad gain bandwidth. This allows to amplify ultrashort, femtosecond pulses. The high thermal conductivity of CALGO:Yb also guarantees efficient heat dissipation during high-power operation, preserving performance stability. Because of these characteristics, CALGO:Yb crystals are perfect for industrial operations requiring a high degree of power and precision, as well as scientific research and medical applications.

CALGO:Yb powder was synthesized from corresponding metal nitrates using the sol-gel method. The phase purity of the powder samples was confirmed using X-ray diffraction (XRD) analysis. The powder was pressed into rods and then used to grow the crystal by the optical floating zone (OFZ) method. Scanning electron microscopy (SEM) images were taken to determine the morphology of the crystal. SEM images revealed defects on the crystal cut surface. On the other hand, it showed a homogenous element distribution. ICP-OES measurement showed that both the powder and the single-crystal had correct stoichiometry, indicating that the melting process did not alter it. The luminescence properties were also investigated, demonstrating the typical emission and excitation spectrum corresponding to ytterbium electron transitions.

This study demonstrated that the OFZ method is suitable for growing CALGO:Yb crystals. However, the crystal exhibited some defects, making it unsuitable for practical use as a laser core. This highlights the need for further research to optimize the crystal growth process.