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1The optimal dopants concentrations search of Yb,Li:ZnWÜ4
laser crystals
O. Lis1*, Yu. Zimina12, P. Volkov3, D. Lis1, K. Subbotin12, A. Titov1, S. Pavlov1'2
1-Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, Russia 2- Mendeleev University of Chemical Technology of Russia: Moscow, Russia 3- NRC "Kurchatov Institute" - IREA Shared Knowledge Center, Moscow, Russia
The results of our attempts to improve Yb segregation coefficient in ZnWO4 crystal and the mechanical straights characteristics of Yb:ZnWO4 laser crystals by the addition of Li+ charge compensator are presented in the talk.
ZnWO4, Yb:ZnWO4 and Yb,Li:ZnWO4 single crystals with various concentrations of Yb3+ and Li+ ions were grown by the Czochralski technique using Pt crucibles. The seeds for the growth were cut from undoped ZnWO4 crystal parallel to the (010) crystallographic plane. Preliminary studies have shown that unlike the case of the undoped crystals, doping of ZnWO4 crystal by Yb3+ ions without the appropriate amount of charge compensator sharply deteriorates the mechanical characteristics of the samples. Yb-doped samples contain numerous cracks, predominantly, along the (010) crystallographic plane.
Atomic emission spectroscopy with inductively coupled plasma, as well as polarized optical absorption spectroscopy were used for the determination of actual dopants concentrations. The mutual influence Yb3+ and Li+ ions onto their segregation coefficients in the crystal was revealed.
Yb,Li:ZnWO4 crystals, grown from the melts, containing 5-5.5 at.% Yb3+ and 8-12 at.% Li+, possess the best hardness and fracture toughness. Less Li+ concentration results in too big difference between the actual Yb3+ and Li+ contents in the crystal, and, hence, in too large amount of Zn vacancies. It substantially weaken the crystal lattice and lead to reduction of the crystal mechanical strength.
This work has been supported by Russian Scientific Fund (grant № 23-22-00416).
