1. Department of Physics, College of Science, Sultan Qaboos University, P. O. Box 36, Al-Khoud 123, Oman
2. Photonics Technology Laboratory, National Electronics and Computer Technology Center (NECTEC), 112 Thailand Science Park, PathumThani 12120, Thailand
3. Center of Research in Optoelectronics, Communication and Control Systems (BUCROCCS), School of Engineering, Bangkok University, PathumThani 12120, Thailand
4. Functional Materials Division, School of Information and Communication Technology, KTH Royal Institute of Technology, Isafjordsgatan 22, SE-164 40 Kista, Stockholm, Sweden