1. Graduate
Institute of Photonics and Optoelectronics, and Department of Electrical
Engineering, National Taiwan University (NTU), No. 1, Roosevelt
Road Sec. 4, Taipei 10617, Taiwan, Republic of China
2. Department
of Photonics and Department of Physics, National Sun Yat-sen University, No. 70, Lien-Hai Rd., Kaohsiung 804, Taiwan, Republic of China
3. Department
of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan, Republic of China
4. Research
Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan, Republic of China