1. Research Scholar, JNTUA, Anantapuramu, India;
2. Department of Physics, Malla Reddy Engineering College (A), Secunderabad, India;
3. Department of Physics, JNTUA College of Engineering, Pulivendula, India;
4. College of Physics and Energy, Shenzhen University, Shenzhen, P.R. China;
5. Department of Physics, Annamacharya Institute of Technology & Sciences, Rajampet, India