LIGHT-TRANSMITTING POLYCRYSTALLINE MATERIAL AND PROCESS FOR PRODUCING SAME
A light-transmitting polycrystalline material having optical properties that continuously change in the material is produced. A slurry which contains single-crystal particles that receive force when placed in a magnetic field is sintered after being subjected to affixing in a magnetic field where the magnetic-flux density changes with respect to the space. For example, a slurry which contains single-crystal particles of YAG to which Er has been added and single-crystal particles of YAG to which no rare-earth elements have been added is subjected to affixing in a magnetic field where the magnetic-field intensity is unevenly distributed. As a result, the portion located in an intense magnetic field gives a laser oscillation region which is rich in the YAG containing Er and in which the crystals have been unidirectionally oriented, while the portion located in a weak magnetic field gives a region which is rich in the YAG containing no rare-earth elements and which transmits light. Thus, a polycrystalline material having both a core that undergoes a laser oscillation and a guide that is located on the periphery of the core and leads excitation light to the core can be produced at one time.