1. Department of Technical Education, Government Polytechnic, Amadalavalasa, Srikakulam 532185, Andhra Pradesh, India
2. Department of Physics, GIT, Gitam University, Visakhapatnam 530045, Andhra Pradesh, India
3. Department of Physics, Andhra University, Visakhapatnam – 530003, Andhra Pradesh, India
4. Department of Physics, RGU-IIIT Nuzvid, Krishna 52120, Andhra Pradesh, India