Growth and second-harmonic-generation of Bi³⁺- or Li⁺-doped GdCa₄O(BO₃)₃ crystals

The bismuth and lithium cations doped GdGa₄O(BO₃)₃ (GdCOB) crystals were successfully grown for the first time. The X-ray powder diffraction (XRPD) shows that the cell parameters of the doped crystals are slightly larger than that of GdCOB. Intracavity second-harmonic-generation (SHG) experiments were carried out on 3×3×6 mm³ GdCOB and doped GdCOB crystals along the phase-matching (PM) direction (θ = 66.8°, φ = 132.6°). The results show that the continuous wavelength (cw) green laser output power is 0.94 W for GdCOB crystals at 10 W LD pump power while it is 1 W and 1.02 W for the bismuth and lithium doped GdCOB crystals, respectively. Considering the fundamental laser power in the cavity, the intracavity SHG conversion efficiency of GdCOB and bismuth, lithium cations doped GdCOB crystals are 21, 22.6 and 23%, respectively. The SHG conversion efficiency is improved by 8 and 10% when GdCOB is doped with bismuth and lithium cations. The effects of the doped cations on growth and SHG properties of GdCOB crystal are discussed.