1. Artificial Crystal Research Center Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS) 585 He-shuo Road Shanghai 201899 P. R. China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. School of Materials and Chemistry University of Shanghai for Science and Technology 516 Jun-gong Road Shanghai 200093 P. R. China
4. NICHe Tohoku University 6-6-10 Aza-Aoba Aramaki Aoba-ku Sendai Miyagi 980-8579 Japan
5. Institute for Materials Research Tohoku University 2-1-1 Katahira, Aoba-ku Sendai Miyagi 980-8577 Japan
6. Institute of Laser Engineering Osaka University 2-6 Yamadaoka Suita Osaka 565-0871 Japan