1. Department of Physics and Applied Physics
2. Yonsei University
3. Seoul 120-749
4. Korea
5. Electronics and Telecommunications Research Institute
6. Semiconductor R&D Center
7. Advanced Photonic Research Institute
8. Gwangju Institute Science and Technology
9. Gwangju 500-712
10. Pohang Accelerator Laboratory
11. Pohang University of Science and Technology
12. Pohang