1. Department of Electronics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu, India.
2. Department of Physics, Bannari Amman Institute of Technology, Sathyamanglam, Tamil Nadu 638401, India.
3. Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu, India.