1. Department of Electrical and Electronic Engineering, Okayama University, Okayama, Okayama 700-8530, Japan
2. NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, USA
3. Metamaterials Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
4. Innovative Photon Manipulation Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan
5. Department of Chemical Science and Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan
6. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
7. Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia