Growth and Second-Harmonic-Generation Properties of Tm³⁺, Yb³⁺, Bi³⁺ and Li⁺ Doped GdCa₄O(BO₃)₃ Crystals

The rare-earth ions (Yb³⁺, Tm³⁺) and Li⁺, Bi³⁺ ions doped GdCa₄O(BO₃)₃ crystals were grown using the Czochralski pulling method. The second-harmonic-generation conversion efficiencies of the GdCOB:Yb and GdCOB:Tm crystals are 31.3% and 33.3%, respectively, while the undoped GdCOB crystal is 27.9%. The conversion efficiencies of Yb³⁺, Tm³⁺ doped GdCOB are improved by 12% and 19%, respectively, compared to that of the undoped one. The conversion efficiencies of Li⁺, Bi³⁺ doped GdCOB crystals are 33% and 38.3%, which are improved by 15% and 37% as compared to that of the undoped crystal. The results are discussed using the anion group theory.