Abstract: Gd_xY_1-xCa₄O(BO₃)₃ (GdYCOB ) crystal is a kind of valuable nonlinear optical crystal. It can
realize THG noncritical phase-matching for Nd:YAG laser and keep stable mechanical and chemical properties. Nd³⁺, Gd³⁺ and Y³⁺
are all rare-earth ions, so we can receive Nd:Gd_xY_1-xCa₄O(BO₃)₃ (Nd:GdYCOB) crystal by a few Nd3+ ions doping. Combined laser action
of the Nd3+ ions and nonlinear optical properties of GdYCOB host crystal in the mixed crystal, a new kind of self-frequency doubling crystal
Nd:GdYCOB was obtained. The synthesis and crystal growth of Nd:GdYCOB crystal were reported in this paper. The transparent spectrum, fluorescent spectrum,
and fluorescence lifetime of Nd:GdYCOB crystal were first measured at room temperature.

Key words: Nd:Gd_xY_1-xCa₄O(BO₃)₃ crysta, self-frequency doubling crystal, czochralski growth, optical spectra, RGB