1. Research Center for Applied Sciences (RCAS), Academia Sinica, Taipei 11529, Taiwan
2. Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University (NCTU), Hsinchu 30010, Taiwan
3. Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia
4. Department of Photonics, National Sun Yat-sen University (NSYSU), Kaohsiung 80424, Taiwan