1. Department of Mechanical Engineering, Chung Yuan Christian University, Taoyuan-32023, Taiwan
2. Center for Condensed Matter Sciences, National Taiwan University, Taipei-10617, Taiwan
3. Department of Photonics Engineering, Technical University of Denmark, Roskilde-4000, Denmark
4. Institute of Physics, Academia Sinica, Taipei-11529, Taiwan
5. Aston Institute of Photonic Technologies, Aston University, Birmingham-B4 7ET, UK
6. Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa-32000, Israel