PROCESS FOR PRODUCING A TRANSLUCENT POLYCRYSTALLINE MATERIAL

Provided is a method for manufacturing a translucent polycrystalline material with optical properties continuously varying in the material. A slurry including a group of single crystal grains that are acted upon by a force when placed in a magnetic field is immobilized in a gradient magnetic field with a spatially varying magnetic flux density and then sintered. For example, where a slurry including a group of single crystal grains of YAG doped with Er and a group of single crystal grains of YAG undoped with a rare earth material is immobilized in a magnetic field with a non-uniform distribution of magnetic field intensity, the region with a strong magnetic field becomes a laser oscillation region that is rich in Er-doped YAG and has aligned crystal orientations, whereas the region with a weak magnetic field becomes a translucent region rich in YAG undoped with a rare earth material. A polycrystalline material can be manufactured in which a core with laser oscillations and a guide surrounding the core and guiding excitation light to the core are obtained at the same time.