New fabrication process of anisotropic laser ceramics

In this research, a new method of "advanced electromagnetic processing" has been established for fabricating transparent rare-earth doped anisotropic ceramics toward the Giant Micro Photonics. We applied it for RE:FAP (RE:Ca₁₀(PO₄)₆F₂) materials that have excellent optical properties such as high absorption efficiency, high emission cross-section and long lifetime. We have discovered that orbital angular momentum of electrons in the rare earth ions doped into anisotropic crystal strongly enhances the net magnetic anisotropy of the material. In the case of 1.8 at.%Yb:YVO₄, the anisotropic magnetization energy U, which is the driving force of magnetic orientation becomes 5 times larger than that of undoped ceramic material at room temperature. This means it is possible to achieve the precise grain orientation of RE-doped ceramics by feeble magnetic field (2 tesla or less), while undoped ceramics require the 5~10 Tesla magnetic field. These results show that the laser grade uni-axially oriented anisotropic ceramics as the new generation of laser ceramics was successfully obtained by newly discovered rare-earth assisted magnetic moment controlling process.