Growth of single crystal with a gradient of concentration of impurities by the Czochralski method using additional liquid charging

Er- and Yb-doped congruent LiNbO3 (CLN) single crystals and Cr3+- and Mg2+-doped stoichiometric LiNbO3 (SLN) single crystals were grown by the Czochralski method using additional liquid charging. Changes in the absorption spectra of the transitions 2F7/2→2F5/2 in Yb3+ ions and 4I15/2→2H11/2 in Er3+ ions along the length of a single-crystal plate correlate with a specific gradient of concentration of Yb3+ and Er3+ ions in the crystal. The correlation of the absorption spectra of the optical centers of Cr3+ ions in stoichiometric LiNbO3 single crystals with the content of magnesium along the length of the crystal is reported.