1. Faculty of Engineering and Science, Western Norway University of Applied Sciences, 5063 Bergen, Norway
2. Department of Physics, Coimbatore Institute of Technology, Coimbatore, Tamil Nadu 641 014, India
3. School of Mechanical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu 632 014, India
4. Department of Physics, Dr. N.G.P. Arts and Science College, Coimbatore, Tamil Nadu 641 048, India