1. Department of Electrical and Electronic Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000 Kajang, Selangor, Malaysia
2. Center for Photonics and Advanced Material Research, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000 Kajang, Selangor, Malaysia
3. Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
4. School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
5. Faculty of Applied Sciences, Universiti Teknologi MARA, Cawangan Sarawak, 94300 Samarahan, Sarawak, Malaysia
6. Faculty of Engineering, Multimedia University, Persiaran Multimedia, 63100 Cyberjaya, Selangor, Malaysia