1. School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Korea
2. Advanced Photonics Research Institute (APRI), Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 61005, Korea
3. Discovery Research, Penn Color, Inc., 2801 Richmond Road, Hatfield, Pennsylvania 19440, United States