1. Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan
2. Department of Physics, Center of Crystal Research, College of Semiconductor and Advanced Technology Research, National Sun Yat-sen University, Kaohsiung, Taiwan
3. Institute of Electronics Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan
4. Department of Photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
5. Institute of Electronics Engineering, National Tsing Hua University, Hsinchu, Taiwan
6. Department of Physics, Military Academy, Kaohsiung, Taiwan