A newly-developed multi-doped red emission single crystal phosphor (Eu³⁺:Sm³⁺:Cr³⁺:YAG) prepared by liquid phase epitaxy on a 54 mm diameter monocrystalline YAG substrate is reported. The chromaticity coordinates of the emission of this material are x=0.6137, y=0.3738, and it is equivalent to a red light of a wavelength of 599 nm with good color saturation. This novel monocrystalline phosphor can withstand incident electron beam with high energy (up to 105 W/m2) without lighting quenching or “burning in”. All these properties show that it′s an ideal red emission material.